help button home button Endocrine Society Endocrinology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Cabrera-Valladares, G.
Right arrow Articles by Fernandez-Mejia, C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cabrera-Valladares, G.
Right arrow Articles by Fernandez-Mejia, C.
Endocrinology Vol. 140, No. 7 3091-3096
Copyright © 1999 by The Endocrine Society

ARTICLES

Effect of Retinoic Acid on Glucokinase Activity and Gene Expression and on Insulin Secretion in Primary Cultures of Pancreatic Islets1

Gabriela Cabrera-Valladares, Michael S. German, Franz M. Matschinsky, Juehu Wang and Cristina Fernandez-Mejia

From the Nutritional Genetics Unit (G.C.V., C.F.M.) Biomedical Research Institute, National University of Mexico, Mexico City, Mexico 04530; Hormone Research Institute (M.S.G., J.W.) University of California San Francisco, San Francisco, California 94143-0534; and Diabetes Research Center (F.M.M.), University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104-6015

Address all correspondence and requests for reprints to: Cristina Fernandez-Mejia, Unidad de Genetica de la Nutricion, Instituto de Investigaciones Biomedicas Universidad Nacional Autónoma de México/Instituto Nacional de Pediatría, Avenida del Iman 1, 4th Floor, Mexico City, C.P. 04530, Mexico. E-mail: crisfern{at}servidor.unam.mx


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
Retinoic acid has manifold effects on pancreatic ß-cells. Previously we reported that retinoic acid increases glucokinase activity and messenger RNA (mRNA) levels in the insulinoma cell line RIN-m5F; however, we could not rule out the possibility that the effect of retinoic acid on RIN-m5F glucokinase was inherent to the cell line or related to its differentiating capacity. In this report, we demonstrate that physiologic concentrations of retinoic acid stimulate glucokinase activity in both fetal islets and differentiated adult islets in culture. In the adult tissue, the response to the retinoid was less pronounced, achieving about half of the maximal effect produced on the fetal tissue. Using the branched DNA (bDNA) assay, a sensitive signal amplification technique, we detected relative increases in glucokinase mRNA levels of 51.8 ± 13.3% and 62.8 ± 16.1% at 12 and 24 h, respectively, in adult islets treated with ]10-6 M retinoic acid. In fetal islets, increases of 55 ± 14.9% and 107 ± 30.5% at 12 and 24 h, respectively, were observed. In transfected fetal islets, retinoic acid increased the activity of the -1000 kb rat glucokinase promoter by 51.3%. Because glucokinase activity controls insulin secretion, we also investigated the effect of retinoic acid on insulin secretion. Treatment with 10-6 M retinoic acid for 24 h increased insulin secretion in both fetal and adult islets; however, the increases on insulin secretion were more pronounced in the mature islets; in contrast, retinoic acid produced higher levels of insulin mRNA in the fetal islets. These data show that retinoic acid increases pancreatic glucokinase in cultured islets and that the mechanism may involve a stimulatory effect on the glucokinase promoter.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
GLUCOKINASE (EC 2.7.1.1) is a tissue-specific enzyme present in hepatocytes, in pancreatic ß cells and in certain rare neuroendocrine cells of the brain and gut (1, 2, 3). Glucokinase plays a key role in glucose homeostasis, regulating insulin secretion in response to glucose in the ß cells (4, 5) and uptake of glucose in the liver (6, 7). In humans, mutations in the glucokinase gene cause maturity-onset-diabetes of the youth (MODY 2) (8) or hyperinsulinemia (9).

Comparison of the pancreatic and hepatic glucokinase gene transcripts reveals tissue specific control of expression and the existence of two distinct promoters in a single glucokinase gene (10, 11). The existence of alternate promoters suggests that separate factors regulate glucokinase transcription in the two tissues. In the liver, glucokinase gene transcription is under multihormonal control (12, 13, 14). Less is known about the transcriptional regulation of pancreatic glucokinase by hormones. Posttranscriptional regulation have been invoked to explain glucose induction of glucokinase (15). In a previous report, we demonstrated that pancreatic glucokinase transcription and activity is also regulated by different lipophilic hormone ligands of the nuclear hormone receptor superfamily, and that this hormonal regulation differs between the hepatic and the pancreatic genes (16).

One member of this family, all-trans-retinoic acid, a derivative of vitamin A and a ligand for a member of the nuclear hormone receptor superfamily, plays an important role in cellular development, cellular growth, and differentiation (17, 18). In cultured cells, the nature of the growth and differentiation response elicited by retinoic acid depends upon the cell line. Thus, retinoic acid induces terminal differentiation of many cell types, including mouse teratocarcinoma stem cells (19), neuroblastoma cells (20), and the promyelocytic cell line, HL-60 (21). In contrast, retinoic acid inhibits the differentiation of chondrocytes (22) and adipocytes (23). The effect of retinoic acid on gene expression is also related to the differentiation state of the cell: retinoic acid induces S14 gene transcription in cultured adipocytes but not preadipocytes (24, 25).

During development, the natural source of retinoids for embryonic tissues is maternal retinol. In view of its highly pleiotropic effects, it is likely that retinoic acid is synthesized from retinol in discrete areas of the embryo, close to its sites of action. It has been suggested (26) that the function of cytosolic retinol binding protein (CRBP) is to concentrate and store retinol in sites where retinoic acid is required in relatively high concentrations, so that retinol can be converted to retinoic acid in relation to specific morphogenetic processes. Conversely, cytosolic retinoic acid binding protein (CRABP) may be expressed by cells whose normal developmental function requires low levels of retinoic acid. In fetal pancreas, homogenous expression of CRBP but not CRABP can be detected (26), suggesting that high concentrations of retinoic acid are important during pancreatic development.

Retinoic acid also affects the function of pancreatic ß-cells: 1) It restores insulin secretion in vitamin A deficient rats (27). 2) It induces both first and second phase insulin secretory responses to glucose in explants of human fetal pancreas, which are normally poorly responsive to glucose (28). 3) It increases insulin production in RINm5F cells (16) and in human islets (29). Finally, retinoic acid increases pancreatic glucokinase activity and messenger RNA (mRNA) levels in the insulinoma cell line RIN-m5F (16); but this effect could be related to the differentiating capacity of retinoic acid because this cell line is relatively undifferentiated in comparison to rat adult islets cells (30, 31) and several manipulation can cause further maturation of these cells (32, 33, 34, 35). Therefore, in this work we analyzed the effect of retinoic acid on glucokinase activity and expression in primary cultures of rat islets in two different stages of maturity to determine if the effect of the retinoid is related to its differentiating actions.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Adult islet culture
Pancreatic islets were isolated by the collagenase method reported by Hiriart and Ramirez (36) from 200–250 g Wistar male rats (Harlan, Mexico City, Mexico) injected ip with 0.25 ml of a 6.3% solution of pentobarbital (Pfiezer, Inc., Mexico City, Mexico). Islets were suspended in RPMI 1640 medium containing 10% FBS and 400 U/ml penicillin, and 200 mg streptomycin (Life Technologies, Inc., Gaithersburg, MD) [supplemented Rosewell Park Memorial Institute (RPMI) 1640 medium] and distributed equally into 60-mm tissue culture dishes (Costar, Cambridge, MA). Cultures were incubated at 37 degree C in a humidified atmosphere of 5% CO2; and after 2–4 h of plating, cells were treated either with retinoic acid or vehicle (dimethylsulfoxide (DMSO; 0.01%) for the times indicated in the text.

Fetal islet culture
Twenty-one-day gestation fetal Wistar rat islets were isolated as described previously (37). Briefly, pancreatic glands obtained from four to six rats were finely minced and digested with collagenase Type D and 2 µl DNase I (Boehringer Mannheim, Mannheim, Germany). The washed digest was suspended in supplemented RPMI 1640 medium and distributed equally into two 60-mm tissue culture dishes (Costar). Cultures were incubated at 37 C in a humidified atmosphere of 5% CO2, after 5 h of plating to deplete fibroblasts, islets were seeded into 60-mm tissue culture dishes (Costar, Cambridge, MA) and treated either with retinoic acid or vehicle (DMSO; 0.01%) for the times indicated in the text.

Glucokinase assay
Seven hundred to 800 islets were harvested and centrifuged at 1,200 rpm. Tissue pellets were lysed in 500 µl reporter lysis buffer (Promega Corp., Madison, WI), vortexed, and cell membranes disrupted by three freeze-thaw cycles. Five hundred microliters of GK buffer consisting of 50 mM Tris (pH 7.6), 4 mM EDTA, 150 mM KCl, 4 mM Mg2SO4, and 2.5 mM dithiothreitol were added. The lysates were then centrifuged at 4 C for 1 h at 35,000 x g, in a Beckman Coulter, Inc. ultracentrifuge model Optima. Supernatants were recovered, and enzymatic activity was assayed as described previously by Walker and Parry (38), using NAD (Sigma Chemical Co., St. Louis, MO) as coenzyme. Glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides (Sigma Chemical Co.), was used as coupling enzyme. Correction for low hexokinase activity was applied by subtracting the activity measured at 0.5 mM glucose from the activity measured at 100 mM glucose. Protein concentrations were determined by Bradford assay (39).

mRNA analysis
Glucokinase, insulin, and actin mRNA were quantified using bDNA technology in a 96-microwell format as previously described for quantification of insulin preRNA (40). All components, including buffers and DNA reagents were obtained from Chiron Corp. (Emeryville, CA). RNA was extracted by either Trizol (Life Technologies, Inc.) or by cell lysis with 400 µl of extraction buffer (78 mM HEPES. pH 8.0/12.5 mM EDTA, pH 8.0/6.27 mM LiCl/1.6 lithium lauryl sulfate/proteinase K (1 mg/ml)/single-stranded DNA (19 µg/ml)/7.8% formamide/0.05% sodium azide/0.05% Proclin 300. RNA samples were mixed with 200 µl extraction buffer, along with proteinase K and glucokinase capture and label probes, loaded in the microwell plate, sealed with an adhesive-backed mylar plate sealer (Microtiter Plate Sealer, Flow Laboratory), and incubated overnight at 63 C in a plate heater to capture the targeted nucleic acids to the oligonucleotide-modified microwell surface. After cooling at room temperature for 10 min, cells were washed twice with wash A (Chiron Corp.). Fifty microliters of bDNA amplifier solution containing the bDNA amplifier probe at 1 pmol/ml in amplifier diluent (Chiron Corp.) were added and hybridized at 53 C for 30 min. After cooling and washing as described above, 50 µl of a mixture containing alkaline phosphatase-conjugated label probes (2 pmol/ml) in label diluent (Chiron Corp.) were added and hybridized at 53 C, for 15 min. The plate was cooled and washed twice in buffer A as above and then washed three times with wash solution B (Chiron Corp.). Finally, 50 µl of chemiluminescent substrate (Lumiphos 530), an enzyme-triggerable dioxetane substrate for alkaline phosphatase, was added, and the plate was incubated at 37 C for 25 min. Light emission was measured in a luminometer at 37 C. Each sample was assayed in triplicate. Each sample was standardized to actin mRNA.

Plasmid constructs
The construction of pFOXCAT1 has been described previously (41). The rat ß cell glucokinase -1000 promoter extends from -1000 to +14 bp and was a gift from M. Magnuson (Vanderbilt University, Nashville, TN) (42).

Fetal islet transfection
Experiments were performed as previously described by German et al. (37); briefly, 21-day gestation fetal Wistar rat islets were isolated and digested for 5 min with collagenase Type P and 2 µl DNase I (Boehringer Mannheim). After 3 h of plating to deplete fibroblasts, islets were recovered and dispersed with trypsin 0.05%, 0.53 mM EDTA (Life Technologies, Inc.). Dispersed islets were incubated at 37 degree C in a humidified atmosphere of 5% CO2, after 3 h of plating to deplete from fibroblasts, cells were harvested by rinsing the plates, pelleted and washed twice in room temperature PBS, resuspended in 0.8 ml PBS with 25 µg of double cesium-purified plasmid DNA and electroporated with a discharge of 175 V, 2,000 µF in a BTX electroporation system model 600 (San Diego, CA). The transfected cells were grown in supplemented RPMI with retinoic acid (10-6 M) or vehicle (DMSO; 0.01%) for approximately 48 h before harvesting and protein extraction. CAT-TLC was performed using 25 µg of protein and to generate enough CAT product, the sample was incubated for 3 h. Acetylated chloramphenicol signals were analyzed using a Phosphoimager 425 (Molecular Dynamics, Inc., Costa Mesa, CA).

Insulin secretion
Adult or fetal islets were isolated and cultured as described above. After 24 h of treatment with retinoic acid (10-6 M or vehicle, DMSO 0.01%), cells were washed twice with secretion buffer containing 20 mM HEPES, 115 mM NaCl, 5 mM NaHCO3, 4.7 mM KCL, 2.6 mM CaCl2, 1.2 mM KH2PO4, and 1.2 mM MgSO4 (pH 7.4). Islets were then incubated for 1 h in secretion buffer containing D-glucose as indicated in the text and figure legends. Insulin concentration was analyzed by RIA (ICN Biomedicals, Inc., CA).

Statistics
Data are presented as mean + SE. Individual comparisons were evaluated by Student’s paired two tailed t test. Multiple comparisons were evaluated using one-way ANOVA. The significance level chosen was P < 0.05.


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
Retinoic acid effect on adult islet glucokinase activity
To investigate if retinoic acid is able to affect this enzyme in the adult differentiated tissue, we analyzed the effect of retinoic acid on glucokinase activity in islets isolated from adult rats. As shown in Fig. 1AGo, retinoic acid doses of 10-6 M increased glucokinase activity by 103 ± 6.4% at 24 h. This effect is slightly decreased at 48 h when an increase of 85 ± 4.1% was observed. The responsiveness of adult islet pancreatic glucokinase to different doses of retinoic acid is shown in Table 1Go; a stimulatory effect was observed at doses as low as 10-8 M, the minimal concentration tested.



View larger version (35K):
[in this window]
[in a new window]
  		Figure 1. Effect of retinoic acid on glucokinase activity in fetal and adult islets. Islets were isolated by collagenase digestion as described in Materials and Methods. Islets were cultured for the indicated periods of time in the presence of vehicle (DMSO; 0.01%) or 10-6 M retinoic acid. A, Adult islets; B, fetal islets. Data are expressed as mean percentages ± SE of glucokinase activity (adult = 97.5 ± 12; fetal =102.5 ± 22 pmol/h·islet); n = 7 or 4 experiments as indicated in the figure. Multiple comparisons were evaluated using one-way ANOVA. *, P <= 0.05; **, P <= 0.0005.

 

View this table:
[in this window]
[in a new window]
  		Table 1. Effect of different dose of retinoic acid on glucokinase activity in fetal and adult islets

 
Retinoic acid effect on fetal islet glucokinase activity
Retinoic acid has been shown to promote fetal islet maturation and insulin secretion in response to glucose (28). We investigated if the effect of retinoic acid on glucokinase is modified by the level of differentiation of the tissue. Studies on 21-day rat fetal islets showed (Fig. 1BGo) that after 24 h treatment with retinoic acid doses of 10-6 M, glucokinase activity increased to 196.6 ± 13.7% (P < 0.005). A weaker stimulatory effect was also observed at 48 h (44.2 ± 3.7%) (P < 0.005). As shown in Table 1Go, the retinoid affects glucokinase activity in the fetal tissue at all the doses tested.

Effect of retinoic acid on glucokinase mRNA levels
We determined if the effect of retinoic acid was related to an increase in glucokinase gene expression. Because glucokinase mRNA levels are low, we adapted the branched DNA (bDNA) assay, a sensitive signal amplification technique, to measure glucokinase mRNA levels. Relative increases of 51.8 ± 13.3 and 62.8 ± 16.1% at 12 and 24 h, respectively, were observed in adult islets treated with retinoic acid doses of 10-6 M (Fig. 2AGo). The effect was detectable after 6 h incubation (18.2 ± 10.7%). In fetal islets increases of 55 ± 14.9% and 107 ± 30.5% at 12 and 24 h, respectively, were observed (Fig. 2BGo).



View larger version (33K):
[in this window]
[in a new window]
  		Figure 2. Effect of retinoic acid on glucokinase mRNA levels. Glucokinase and actin mRNA were quantified using bDNA technology. Islets were cultured for the indicated periods of time in the presence of vehicle (DMSO; 0.01%) or 10-6 M retinoic acid. A, Adult islets; B, fetal islets. Each sample was standardized to actin. Data are expressed as relative to that measured in cells incubated with vehicle. Each value represents the mean ± SE of six or three experiments as indicated in the figure. Multiple comparisons were evaluated using one-way ANOVA. *, P < 0.05.

 
Effect of retinoic acid on glucokinase promoter activity
A construct containing -1000 kb of pancreatic glucokinase promoter driving the chloramphenicol acetyl transferase (CAT) reporter gene was transfected in primary cultures of fetal islets. An increase of 51.3 ± 19.1% of glucokinase promoter activity as measured by CAT enzyme activity (n = 5), (Fig. 3Go), was observed after 48 h of treatment with retinoic acid doses of 10-6 M. No effect was observed on the empty pFOX-CAT1 vector (Control = 100%, retinoic acid = 95 ± 9.3%).



View larger version (21K):
[in this window]
[in a new window]
  		Figure 3. Effect of retinoic acid on glucokinase promoter activity. Fetal islets were transfected with pFOXCAT1 containing -1000 to +14 bp of rat ß cell glucokinase promoter. The cells were then incubated in medium with vehicle (DMSO; 0.01%) or 10-6 M retinoic acid for approximately 48 h. CAT activity was then assayed in 25 µg protein of the cell extracts and expressed relative to that measured in cells incubated with vehicle. Each value represents the mean ± SE of five experiments. Significance was assessed by Student’s unpaired two-tailed t test. *, P <= 0.05

 
Insulin secretion and mRNA levels
Because glucokinase activity is a determinant of insulin secretion (4, 5), we analyzed the effect of retinoic acid on insulin release at two different concentrations of glucose. As can be seen in Fig. 4Go, 24 h of treatment with (10-6 M) of the retinoid increased insulin release in either adult islets or in fetal islets. In the fully mature islets (panel A), retinoic acid increased insulin secretion by 139.1 ± 39 and 60.1 ± 17% at 5.5 and 16 mM glucose, respectively (P < 0.05). In the fetal islets, which are normally poorly responsive to glucose, retinoic acid modestly increased insulin release by 33.1 ± 7 and 23.7 ± 7% at 5.5 and 16 mM of glucose, respectively (P < 0.05) (panel B). We also determined the effect of retinoic acid on insulin mRNA by the bDNA method. Treatment with 10-6 M of retinoic acid for 24 h increased insulin message by 48.2 ± 9.1% (P < 0.05) n = 5 in the adult islets and by 79.7 ± 20% in the fetal islets (P < 0.05) n = 5.



View larger version (32K):
[in this window]
[in a new window]
  		Figure 4. Effect of retinoic acid on insulin secretion. Islets were cultured in the presence of vehicle (DMSO; 0.01%) or 10-6 M retinoic acid. A, Adult islets; B, fetal islets. Open bars, Control; shaded bars, retinoic acid. After 24 h incubation, islets were washed and then incubated in 2 ml secretion buffer containing 5.5 or 16 mM glucose. After 1 h incubation, medium was collected. The insulin concentration was analyzed by RIA. Data are expressed in terms of mean percentages ± SE of insulin secretion above the corresponding untreated controls. Absolute values: Control adult 5.5 mM glucose = 25.5 ± 3, fetal control 5.5 mM glucose = 1.2 ± 0.2 µU/h·islet,); (insulin secretion ratios 16/5.5 mM. Adult islets = 1.83 ± 0.11%, fetal islets = 1.26 ± 0.06). n = 6 or 3 experiments as indicated in the figure. Multiple comparisons were evaluated using one-way ANOVA. *, P < 0.05.

 

   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
In the present study, we demonstrate that retinoic acid can stimulate glucokinase gene expression and glucokinase enzyme activity in mature, fully differentiated pancreatic islets as well as in immature fetal islets, although these responses are somewhat greater in fetal islets. Although retinoic acid may be involved in maturation of the ß-cell glucose sensing system during fetal development, as has been proposed previously (28), adult islets clearly retain the capacity to increase glucokinase levels and activity in response to retinoic acid.

Retinoic acid effects on differentiation, cellular growth, and gene expression are mediated through the activation of its nuclear receptors (7, 18). The presence of retinoic acid nuclear receptors RXR, RAR-{alpha}, and RAR-{gamma} as well as high levels of CRBP and CRABP has been reported in fetal and adult islets as well as in pancreatic cell lines (26, 29, 43, 44). Doses of retinoic acid that correspond to the doses required for activation of its nuclear receptor (10-9 to 10-8 M) (45) increased glucokinase activity in either fetal or adult islets, suggesting a physiological effect of the retinoid on pancreatic glucokinase.

Retinoic acid regulation of ß-cell genes is not unprecedented. Clark et al. (29) have demonstrated that the human insulin promoter activity is also activated by retinoic acid. In this work we demonstrated the ability of retinoic acid to activate the -1000 kb ß-cell glucokinase promoter, suggesting that retinoids increase glucokinase activity by activating transcription of the gene. To our knowledge, the studies presented here represent the first report on the physiological regulation of the glucokinase promoter. Current studies in our laboratory are investigating the mechanisms by which retinoic acid activate the pancreatic glucokinase promoter.

In a previous study (16), we have shown that retinoic acid increases insulin mRNA levels in the undifferentiated cell line RIN-m5F; however, we could not rule out the possibility that the effect of the retinoid was related to its differentiating capacity or a response limited to the particular cell line. In the present study, we demonstrate that, similar to its effect on glucokinase, retinoic acid can stimulate insulin gene expression in mature, fully differentiated pancreatic islets as well as in immature fetal islets. Retinoic acid has been shown to increase human insulin mRNA through a tandem repeat of three half sites of the retinoic acid/thyroid hormone regulatory elements (RARE/TRE) closely matching the RARE/TRE consensus AGGTCA at -1037 to -1006 bp in the human insulin promoter. No similar sequences are present in the rat genes. It has been reported that glucose increases insulin mRNA levels by signals coming from the glycolytic pathway (46). Because glucokinase activity governs glycolysis, it is possible that increases of metabolic signals from glycolysis due to the increased activity of glucokinase accounted for the increases observed on insulin mRNA levels. Other plausible explanations are that retinoic acid increases insulin transcriptional factor(s), which in turn increase insulin expression, or that the retinoid increases insulin mRNA stability. However, further studies will be required to determine the mechanisms by which retinoic acid regulate insulin gene expression in the rat.

The studies presented here also demonstrate that retinoic acid treatment can increase insulin secretion in either the adult and the fetal islets; however, a stronger effect was observed in the fully mature adult islets where the glycolitic flux regulated by glucokinase initiate the cascade of events in the signal transduction required for insulin secretion (4, 5). In contrast, in the fetal islets, retinoic acid produced only a modest increase on insulin secretion, in spite of the larger increases produced by the retinoid on glucokinase activity and insulin mRNA levels. Taken together, these data support previous observations suggesting that glucokinase activity and insulin secretion is uncoupled in the fetal islets (47). A functional role of retinoic acid on insulin secretion was suggested in vitamin A-deficient rats (27), the studies presented herein, demonstrate that retinoic acid can affect, as well, insulin secretion in islets from normal rats.

Defects in the normal regulation of islet function by retinoids could contribute to some forms of diabetes in humans. In malnutrition-related diabetes mellitus, vitamin A is reduced in all malnourished diabetic patients when compared with malnourished controls (48). Furthermore, it has been proposed (49) that poor nutrition in fetal and early infant life is detrimental to the development and function of the pancreatic ß cells and predisposes to the later development of type 2 diabetes. The role of vitamin A deficiency as a risk factor in diabetes underlines the significance of understanding the role of retinoids in pancreatic development and function.


   Acknowledgments
 
The authors are grateful to Dr. Marcia Hiriart and Carmen Soto Sanchez for their advice on the isolation of adult islets. We are also indebted to Dr. M. Magnuson (Vanderbilt University) for the glucokinase promoter plasmid. We also thank Mr. Felipe Najera, Moises Paniagua, and the members of the Purchasing Department of Instituto de Investigaciones Biomédicas.


   Footnotes
 
1 This work was supported by Direccion General de Asantos del Personal Académico IN-210894, University California Mexus, and NIH RO1-DK-48281 grants. Back

Received August 31, 1998.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Weinhouse S 1976 Regulation of glucokinase in liver. Curr Top Cell Regul 11:1–50[Medline]
  2. Bedoya FJ, Matschinsky FM, Shimizu T, O’Neil JJ, Appel MC 1986 Differential regulation of glucokinase activity in pancreatic islet and liver in the rat. J Biol Chem 261:10760–10764[Abstract/Free Full Text]
  3. Jetton TL, Liang Y, Pettepher C C, Zimmerman EC, Cox FG, Horvath K, Matschinsky FM, Magnuson MA 1994 Analysis of upstream glucokinase promoter activity in transgenic mice and identification of glucokinase in rare neuroendocrine cells in brain and gut. J Biol Chem 269:3641–3654[Abstract/Free Full Text]
  4. Meglasson MD, Matschinsky FM 1986 Pancreatic islet glucose metabolism and regulation of insulin secretion. Diabetes Metab Rev 2:163–214[Medline]
  5. Matschinsky FM 1996 A lesson in metabolic regulation inspired by the glucokinase glucose sensor paradigm. Diabetes 45:223–242[Abstract]
  6. Granner D, Pilkis S 1990 The genes of hepatic glucose metabolism. J Biol Chem 265:10173–10176[Free Full Text]
  7. Ferre T, Riu E, Bosch F, Valera A 1996 Evidence from transgenic mice that glucokinase is rate limiting for glucose utilization in the liver. FASEB J 10:1213–1218[Abstract]
  8. Velho G, Frogel P, Clement K, Pueyo ME, Rakotoambinina B, Zouali H, Passa P, Cohen D, Robert JJ 1992 Primary pancreatic ß-cell defect caused by mutations in glucokinase gene in kindreds of maturity onset diabetes of the young. Lancet 340:444–448[CrossRef][Medline]
  9. Glaser B, Kesevan P, Heyman M, Davis E, Cuesta A, Buchs A, Stanley CA, Thornton PS, Permutt MA, Matschinsky FM, Herold KC 1998 Familial hyperglycemia caused by an activating glucokinase mutation. N Engl J Med 338:226–230[Free Full Text]
  10. Magnuson MA, Shelton KD 1989 An alternate promoter in the glucokinase gene is active in the pancreatic beta cell. J Biol Chem 264:15936–15942[Abstract/Free Full Text]
  11. Magnuson MA 1990 Glucokinase gene structure. Functional implications of molecular genetic studies. Diabetes 39:523–527[Abstract]
  12. Sibrowski W, Seitz H 1980 Hepatic glucokinase turnover in intact and adrenalectomized rats in vivo. Eur J Biochem 113:121–129[Medline]
  13. Iynedjian PB, Jotterland D, Nouspikel T, Asfari M, Pilot PR 1989 Transcriptional induction of glucokinase gene by insulin in cultured liver cells and its repression by glucagon-cAMP system. J Biol Chem 246:21824–21829
  14. Minderop RH, Hoeppner W, Seitz HJ 1987 Regulation of hepatic glucokinase gene expression. Role of carbohydrates, glucocorticoid and thyroid hormones. Eur J Biochem 164:181–187[Medline]
  15. Liang Y, Najafi H, Smith RM, Zimmerman EC, Magnuson MA, Tal M, Matschinsky FM 1992 Concordant glucose induction of glucokinase, glucose usage, and glucose-stimulated insulin release in pancreatic islets maintained in organ culture. Diabetes 41:792–806[Abstract]
  16. Fernández-Mejía C, Davison MB 1992 Regulation of glucokinase and proinsulin gene expression and insulin secretion in RIN-m5F cells by dexamethasone, retinoic acid and thyroid hormones. Endocrinology 120:1660–1668
  17. Thaller C, Eichele G 1987 Identification and spatial distribution of retinoids in the developing chick limb bud. Nature 327:625–628[CrossRef][Medline]
  18. Kastner P, Mark M, Chambon P 1995 Nonsteroid nuclear receptors: what are genetic studies telling us about their role in real life? Cell 83:859–869[CrossRef][Medline]
  19. Strickland S, Mahdavi V 1978 The induction of differentiation in teratocarcinoma stem cells by retinoic acid. Cell 15:393–403[CrossRef][Medline]
  20. Haussler M, Sidell N, Kelly M 1983 Specific high affinity binding and biological action of retinoic acid in human neuroblastoma cell lines. Proc Natl Acad Sci USA 80:5525–5529[Abstract/Free Full Text]
  21. Breitman TR, Selonick SE, Collins SJ 1980 Induction of differentiation of human promyelocytic leukemia cell line (HL-60) by retinoic acid. Proc Natl Acad Sci USA 77:2936–2940[Abstract/Free Full Text]
  22. Benya PD, Brown PD, Padilla SR 1988 Microfilament modification by dihydrocytochalasin B causes retinoic acid modulate chondrocytes to express the differentiated collagen phenotype without changes in shape. J Cell Biol 106:161–165[Abstract/Free Full Text]
  23. Pairault J, Quignard-Boulange A, Dugail I, Lasnier F 1988 Differential effects of retinoic acid upon early and late events in adipocyte conversion of 3T3 preadipocytes. Exp Cell Res 177:27–36[CrossRef][Medline]
  24. Lepar GJ, Jump DB 1992 Retinoic acid and dexamethasone interact to regulate S14 transcription in 3T3–F44A adipocytes. Mol Cell Endocrinol 84:65–71[CrossRef][Medline]
  25. MacDougald OA, Jump DB 1992 Localization of an adipocyte-specific retinoic acid response domain controlling S14 gene transcription. Biochem Biophys Res Commun 188:470–476[CrossRef][Medline]
  26. Dolle P, Ruberte E, Leroy P, Morris-Kay G, Chambon P 1990 Retinoic acid receptors and cellular retinoic binding proteins. 1. A systematic study of their differential pattern of transcription during mouse organogenesis. Development 110:1133–1151[Abstract/Free Full Text]
  27. Chertow BS, Blaner WS, Baranetsky NG, Sivitz WI, Cordle MB, Thompson D, Meda P 1987 Effects of vitamin A deficiency and repletion on rat insulin secretion in vivo and in vitro from isolated islets. J Clin Invest 79:163–169
  28. Tuch BE, Osgerby KJ 1990 Maturation of insulinogenic response to glucose in human fetal pancreas with retinoic acid. Horm Metab Res [Suppl] 25:233–238[Medline]
  29. Clark AR, Wilson ME, London NJ, James RF, Docherty K 1995 Identification and characterization of a functional retinoic acid/thyroid hormone response element upstream the human insulin enhancer. Biochem J 309:863–870
  30. Chick WL, Warren S, Chute RN, Like AA, Lauris V, Kitchen KC 1977 A transplantable insulinoma in rats. Proc Natl Acad of Sci USA 74:628–633[Abstract/Free Full Text]
  31. Praz GA, Halban PA, Wollheim CB, Strauss AJ, Renold AE 1983 Regulation of immuno-reactive-insulin release from a rat cell line RINm5F. Biochem J 210:345–352[Medline]
  32. Gardner SL, Dotta F, Nayak RC, George KL, Eisenbarth GS, Halban PA 1989 Modulation by sodium butyrate of the differentiated status of a clonal pancreatic beta cell line (RIN). Diabetes Res 12:93–99[Medline]
  33. Powers AC, Philippe J, Herman H, Habner JF 1988 Sodium butyrate increased glucagon and insulin gene expression by recruiting immunocytochemically negative cells to produce hormone. Diabetes 37:1405–1410[Abstract]
  34. Fernandez-Mejia C, Davidson MB 1993 Effect of sodium butyrate on glucose transport and glucose-phosphorylating enzymes in RIN-m5F cells. Pancreas 8:589–596[Medline]
  35. Muschel R, Khouty G, Reid LM 1986 Regulation of insulin mRNA abundance and adenylation: dependence on hormones and matrix substrata. Mol Cell Biol 6:337–341[Abstract/Free Full Text]
  36. Hiriart M, Ramirez-Medeles MC 1991 Functional subpopulations of individual pancreatic ß cells in culture. Endocrinology 128:3193–3198[Abstract]
  37. German MS, Moss LM, Rutter WJ 1990 Regulation of insulin gene expression by glucose and calcium in transfected primary islet cultures. J Biol Chem 265:22063–22066[Abstract/Free Full Text]
  38. Walker DG, Parry MJ 1966 Glucokinase. In: Colowick SP, Kaplan NO (eds) Methods Enzymol. Academic Press, New York, London, vol 9:381–383
  39. Bradford MM 1976 A rapid sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein dye binding. Anal Biochem 72:248–254[CrossRef][Medline]
  40. Wang J, Shen L, Najafi H, Kolberg J, Matschinsky FM, Urdea M, German M 1997 Regulation of insulin preRNA splicing by glucose. Proc Natl Acad Sci USA 94:4360–4365[Abstract/Free Full Text]
  41. German MS, Wang J 1994 The insulin gene contains multiple transcriptional elements that respond to glucose. Mol Cell Biol 14:4067–4075[Abstract/Free Full Text]
  42. Shelton KD, Franklin AJ, Khoor A, Beechem J, Magnuson MA 1992 Multiple elements in upstream glucokinase contribute to transcription in insulin cells. Mol Cell Biol 12:4578–4589[Abstract/Free Full Text]
  43. Kato M, Blaner WS, Mertz JR, Das K, Kato, Kuniyo, Goodman DWS 1985 Influence of retinoid nutritional status on cellular retinol and cellular retinoic acid binding protein concentrations in various rat tissues. J Biol Chem 260:4832–4838[Abstract/Free Full Text]
  44. Chertow BS, Blaner WS, Rajan DA, Primerano DA, Meda P, Cirulli V, Krozowski Z, Smith R, Cordle MB 1993 Retinoic acid receptor, cytosolic retinol-binding and retinoic acid-binding protein mRNA transcripts and proteins in rat insulin-secreting cells. Diabetes 42:1109–1114[Abstract]
  45. Brand N, Petkovich M, Krust A, Chambon P, Thé HU, Tiollais P, Dejean A 1988 Identification of a second human retinoic acid receptor. Nature 332:850–852[CrossRef][Medline]
  46. German MS 1993 Glucose sensing in pancreatic islet beta cells: the key role of glucokinase and the glycolytic intermediates. Proc Natl Acad Sci 90:1781–1785[Abstract/Free Full Text]
  47. Tu J, Tuch BE 1996 Glucose regulates the maximal velocities of glucokinase and glucose utilization in the mature fetal rat pancreatic islet. Diabetes 45:1068–1075[Abstract]
  48. McDonagh M, Liaquat A, Kahn A, Flatt PR, Barnett YA, Barnett CR 1997 Antioxidant status, oxidative stress, and DNA damage in the aetiology of malnutrition related diabetes mellitus. Biochem Soc Trans 25:146S (Abstract)
  49. Hales CN, Barker DJ 1992 Type 2 diabetes mellitus: the thrifty phenotype hypothesis. Diabetologia 35:595–601[CrossRef][Medline]



This article has been cited by other articles:


Home page
 EndocrinologyHome page
K. Yoshida, K. Murao, H. Imachi, W. M. Cao, X. Yu, J. Li, R. A. M. Ahmed, N. Kitanaka, N. C. W. Wong, T. G. Unterman, et al.
Pancreatic Glucokinase Is Activated by Insulin-Like Growth Factor-I
Endocrinology, June 1, 2007; 148(6): 2904 - 2913.
[Abstract] [Full Text] [PDF]

Home page
 EndocrinologyHome page
H. Zitzer, W. Wente, M. B. Brenner, S. Sewing, K. Buschard, J. Gromada, and A. M. Efanov
Sterol Regulatory Element-Binding Protein 1 Mediates Liver X Receptor-{beta}-Induced Increases in Insulin Secretion and Insulin Messenger Ribonucleic Acid Levels
Endocrinology, August 1, 2006; 147(8): 3898 - 3905.
[Abstract] [Full Text] [PDF]

Home page
 Eur J EndocrinolHome page
S Corbetta, R Angioni, A Cattaneo, P Beck-Peccoz, and A Spada
Effects of retinoid therapy on insulin sensitivity, lipid profile and circulating adipocytokines
Eur. J. Endocrinol., January 1, 2006; 154(1): 83 - 86.
[Abstract] [Full Text] [PDF]

Home page
 DiabetesHome page
A. M. Efanov, S. Sewing, K. Bokvist, and J. Gromada
Liver X Receptor Activation Stimulates Insulin Secretion via Modulation of Glucose and Lipid Metabolism in Pancreatic Beta-Cells
Diabetes, December 1, 2004; 53(suppl_3): S75 - S78.
[Abstract] [Full Text] [PDF]

Home page
 DiabetesHome page
S. S. Tulachan, R. Doi, Y. Kawaguchi, S. Tsuji, S. Nakajima, T. Masui, M. Koizumi, E. Toyoda, T. Mori, D. Ito, et al.
All-Trans Retinoic Acid Induces Differentiation of Ducts and Endocrine Cells by Mesenchymal/Epithelial Interactions in Embryonic Pancreas
Diabetes, January 1, 2003; 52(1): 76 - 84.
[Abstract] [Full Text] [PDF]

Home page
 DiabetesHome page
F. M. Matschinsky
Regulation of Pancreatic {beta}-Cell Glucokinase: From Basics to Therapeutics
Diabetes, December 1, 2002; 51(90003): S394 - 404.
[Abstract] [Full Text] [PDF]

Home page
 J. Histochem. Cytochem.Home page
A. N. Player, L.-P. Shen, D. Kenny, V. P. Antao, and J. A. Kolberg
Single-copy Gene Detection Using Branched DNA (bDNA) In Situ Hybridization
J. Histochem. Cytochem., May 1, 2001; 49(5): 603 - 612.
[Abstract] [Full Text]

Home page
 EndocrinologyHome page
S. Morimoto, C. Fernandez-Mejia, G. Romero-Navarro, N. Morales-Peza, and V. DÍaz-Sánchez
Testosterone Effect on Insulin Content, Messenger Ribonucleic Acid Levels, Promoter Activity, and Secretion in the Rat
Endocrinology, April 1, 2001; 142(4): 1442 - 1447.
[Abstract] [Full Text]

Home page
 EndocrinologyHome page
C. Fernandez-Mejia, J. Vega-Allende, A. Rojas-Ochoa, M. Rodriguez-Dorantes, G. Romero-Navarro, F. M. Matschinsky, J. Wang, and M. S. German
Cyclic Adenosine 3',5'-Monophosphate Increases Pancreatic Glucokinase Activity and Gene Expression
Endocrinology, April 1, 2001; 142(4): 1448 - 1452.
[Abstract] [Full Text]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Purchase Article
Right arrow View Shopping Cart
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Cabrera-Valladares, G.
Right arrow Articles by Fernandez-Mejia, C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cabrera-Valladares, G.
Right arrow Articles by Fernandez-Mejia, C.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Endocrinology Endocrine Reviews J. Clin. End. & Metab.
Molecular Endocrinology Recent Prog. Horm. Res. All Endocrine Journals