| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
ARTICLES |
Department of Biochemistry, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
Address all correspondence and requests for reprints to: Jean-Guy LeHoux, University of Sherbrooke, Department of Biochemistry, Faculty of Medicine, Sherbrooke, Québec J1H 5N4, Canada.
The purpose of this study was to evaluate the effects of acute (a single injection) and chronic stimulation (twice daily injection for 9 days) by ACTH on changes occurring in the temporal expression of steroidogenic enzymes in the rat adrenal in vivo. Under acute ACTH stimulation, the level of steroidogenic acute regulatory protein (StAR) messenger RNA (mRNA) was increased within 0.5 h in both zona glomerulosa (ZG) and zona fasciculata-reticularis (ZFR), with maximal increases of 220370% and 300350% in the ZG and ZFR, respectively. Increases in the levels of StAR protein in homogenates were also found in the ZG (700%) and the ZFR (300%), but were delayed compared with those of their mRNA. Furthermore, the increase in mitochondrial StAR protein was concomitant with that in the homogenate, indicating that the entry of StAR into mitochondria might not be necessary to increase steroidogenesis during the early stimulatory phase. The levels of c-jun, c-fos, junB, and fosB mRNA in ZG and ZFR were also rapidly maximally elevated within 0.51 h after ACTH administration and fell to near control levels 5 h posttreatment. The levels of c-jun protein were already increased in both zones at 1 h, reached 200% at 3 h, and remained elevated 5 h post-ACTH treatment. The levels of c-Fos protein were maximally increased by 240% in both zones after 1 h and decreased thereafter to control values at 5 h. Few changes were observed in the adrenal protein contents of cholesterol side-chain cleavage cytochrome P450 (P450scc), cytochrome P450 11ß-hydroxylase (P450C11), cytochrome P450 21-hydroxylase (P450C21), and 3ß-hydroxysteroid dehydrogenase (3ßHSD). Under chronic stimulation by ACTH, we observed elevations in the levels of plasma corticosteroids and changes in the mRNA and protein levels of many adrenal steroidogenic enzymes in both zones. In the ZG, administration of ACTH for 9 days provoked an increase in the level of StAR mRNA (210270%) and a decrease in the levels of 3ßHSD, cytochrome P450 aldosterone synthase (P450aldo), and AT1 receptor mRNA (by 40%, 70%, and 90%, respectively), whereas the levels of P450scc and P450C21 mRNA did not differ significantly from the control values. Western blotting analysis showed that the adrenal ZG protein levels of StAR and P450scc were increased (150%), 3ßHSD was not changed, and P450C21 was decreased by 70%. In the ZFR, the levels of P450scc and StAR mRNAs were increased (260% and 570870%, respectively). The levels of 3ßHSD, P450C21, and P450C11 mRNA did not differ from control values in that zone. Western blotting analysis showed that the ZFR protein level of 3ßHSD was not changed, P450scc and P450C21 were decreased by 40% and 60%, respectively, and StAR was increased by 160%. Although c-fos and fosB mRNAs were undetectable after 9 days of chronic ACTH treatment, c-jun mRNA and its protein were still detectable, suggesting a basic role for this protooncogene in maintaining the integrity and function of the adrenal cortex. When dexamethasone was administered to rats for 5 days to inhibit their ACTH secretion, the mRNA levels of many steroidogenic enzymes were decreased, with the exception of StAR, 3ßHSD, and P450aldo. These results confirm the importance of physiological concentrations of ACTH in maintaining normal levels of adrenocortical enzymes and also indicate that in addition to ACTH, other factors are involved in controlling the expression of StAR, 3ßHSD, and P450aldo.
In conclusion, we showed that ACTH acutely increases StAR mRNA followed, after a delay, by an increase in the level of StAR protein; this suggests that posttranslational modifications of the StAR precursor occurred during the early stimulatory phase and before the apparent translation of the newly formed mRNA. The rapid induction of protooncogenes suggests their participation in the action of ACTH to stimulate steroidogenesis. Under chronic stimulation by ACTH, adrenals were hypertrophied, and the expression of many steroidogenic enzymes was modified, particularly the level of StAR protein was increased in the ZG and ZFR, confirming the importance of this protein in the control of steroidogenesis in a situation similar to that of Cushings syndrome.
This article has been cited by other articles:
![]() |
J. Castillo, B. Castellana, L. Acerete, J. V Planas, F. W Goetz, S. Mackenzie, and L. Tort Stress-induced regulation of steroidogenic acute regulatory protein expression in head kidney of Gilthead seabream (Sparus aurata) J. Endocrinol., February 1, 2008; 196(2): 313 - 322. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. G. Romero, M. W. Plonczynski, B. L. Welsh, C. E. Gomez-Sanchez, M. Y. Zhou, and E. P. Gomez-Sanchez Gene expression profile in rat adrenal zona glomerulosa cells stimulated with aldosterone secretagogues Physiol Genomics, December 19, 2007; 32(1): 117 - 127. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. F Nogueira, C. A Vargas, M. Otis, N. Gallo-Payet, W. B Bollag, and W. E Rainey Angiotensin-II acute regulation of rapid response genes in human, bovine, and rat adrenocortical cells J. Mol. Endocrinol., December 1, 2007; 39(6): 365 - 374. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. G. Romero, S. Rilli, M. W. Plonczynski, L. L. Yanes, M. Y. Zhou, E. P. Gomez-Sanchez, and C. E. Gomez-Sanchez Adrenal transcription regulatory genes modulated by angiotensin II and their role in steroidogenesis Physiol Genomics, June 19, 2007; 30(1): 26 - 34. [Abstract] [Full Text] [PDF] |
||||
![]() |
I.-C. Guo, C.-Y. Huang, C.-K. L. Wang, and B.-c. Chung Activating Protein-1 Cooperates with Steroidogenic Factor-1 to Regulate 3',5'-Cyclic Adenosine 5'-Monophosphate-Dependent Human CYP11A1 Transcription in Vitro and in Vivo Endocrinology, April 1, 2007; 148(4): 1804 - 1812. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. G Ferreira, C. D Cruz, D. Neves, and D. Pignatelli Increased extracellular signal regulated kinases phosphorylation in the adrenal gland in response to chronic ACTH treatment J. Endocrinol., March 1, 2007; 192(3): 647 - 658. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. M. Ulrich-Lai, H. F. Figueiredo, M. M. Ostrander, D. C. Choi, W. C. Engeland, and J. P. Herman Chronic stress induces adrenal hyperplasia and hypertrophy in a subregion-specific manner Am J Physiol Endocrinol Metab, November 1, 2006; 291(5): E965 - E973. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. C. Carey, Y. Su, N. K. Valego, and J. C. Rose Infusion of ACTH stimulates expression of adrenal ACTH receptor and steroidogenic acute regulatory protein mRNA in fetal sheep Am J Physiol Endocrinol Metab, August 1, 2006; 291(2): E214 - E220. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Aluru and M. M. Vijayan Aryl Hydrocarbon Receptor Activation Impairs Cortisol Response to Stress in Rainbow Trout by Disrupting the Rate-Limiting Steps in Steroidogenesis Endocrinology, April 1, 2006; 147(4): 1895 - 1903. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Simard, M.-L. Ricketts, S. Gingras, P. Soucy, F. A. Feltus, and M. H. Melner Molecular Biology of the 3{beta}-Hydroxysteroid Dehydrogenase/{Delta}5-{Delta}4 Isomerase Gene Family Endocr. Rev., June 1, 2005; 26(4): 525 - 582. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Aluru, R. Renaud, J. F. Leatherland, and M. M. Vijayan Ah Receptor-Mediated Impairment of Interrenal Steroidogenesis Involves StAR Protein and P450scc Gene Attenuation in Rainbow Trout Toxicol. Sci., April 1, 2005; 84(2): 260 - 269. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Mallet, O. Feraud, G. Ouengue-Mbele, I. Gaillard, N. Sappay, D. Vittet, and I. Vilgrain Differential expression of VEGF receptors in adrenal atrophy induced by dexamethasone: a protective role of ACTH Am J Physiol Endocrinol Metab, January 1, 2003; 284(1): E156 - E167. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. M. Chinn, D. Ciais, S. Bailly, E. Chambaz, J. LaMarre, and J.-J. Feige Identification of Two Novel ACTH-Responsive Genes Encoding Manganese-Dependent Superoxide Dismutase (SOD2) and the Zinc Finger Protein TIS11b [Tetradecanoyl Phorbol Acetate (TPA)-Inducible Sequence 11b] Mol. Endocrinol., June 1, 2002; 16(6): 1417 - 1427. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Kusakabe, T. Todo, H. J. McQuillan, F. W. Goetz, and G. Young Characterization and Expression of Steroidogenic Acute Regulatory Protein and MLN64 cDNAs in Trout Endocrinology, June 1, 2002; 143(6): 2062 - 2070. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Cherradi, A. M. Capponi, R. C. Gaillard, and F. P. Pralong Decreased Expression of Steroidogenic Acute Regulatory Protein: A Novel Mechanism Participating in the Leptin-Induced Inhibition of Glucocorticoid Biosynthesis Endocrinology, August 1, 2001; 142(8): 3302 - 3308. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Lacroix, N. N'Diaye, J. Tremblay, and P. Hamet Ectopic and Abnormal Hormone Receptors in Adrenal Cushing's Syndrome Endocr. Rev., February 1, 2001; 22(1): 75 - 110. [Abstract] [Full Text] |
||||
![]() |
M. L. Bland, C. A. M. Jamieson, S. F. Akana, S. R. Bornstein, G. Eisenhofer, M. F. Dallman, and H. A. Ingraham Haploinsufficiency of steroidogenic factor-1 in mice disrupts adrenal development leading to an impaired stress response PNAS, December 19, 2000; 97(26): 14488 - 14493. [Abstract] [Full Text] [PDF] |
||||
![]() |
J.-G. Lehoux, D. B. Hales, A. Fleury, N. Brière, D. Martel, and L. Ducharme The in Vivo Effects of Adrenocorticotropin and Sodium Restriction on the Formation of Different Species of Steroidogenic Acute Regulatory Protein in Rat Adrenal Endocrinology, November 1, 1999; 140(11): 5154 - 5164. [Abstract] [Full Text] |
||||
![]() |
H. Raff, B. M. Jankowski, E. D. Bruder, W. C. Engeland, and M. K. Oaks The Effect of Hypoxia from Birth on the Regulation of Aldosterone in the 7-Day-Old Rat: Plasma Hormones, Steroidogenesis in Vitro, and Steroidogenic Enzyme Messenger Ribonucleic Acid Endocrinology, July 1, 1999; 140(7): 3147 - 3153. [Abstract] [Full Text] |
||||
![]() |
S. A. Lloyd-MacGilp, L. Torielli, S. Bechtel, G. Tripodi, C. E. Gomez-Sanchez, L. Zagato, R. Bernhardt, and C. J. Kenyon Mutations in aldosterone synthase gene of Milan hypertensive rats: phenotypic consequences Am J Physiol Endocrinol Metab, March 1, 2002; 282(3): E608 - E617. [Abstract] [Full Text] [PDF] |
||||
| 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 |