Endocrinology, Vol 135, 2526-2532, Copyright © 1994 by Endocrine Society

ARTICLES

Induction of vasoactive intestinal peptide gene expression and prolactin secretion by insulin-like growth factor I in rat pituitary cells: evidence for an autoparacrine regulatory system

JI Lara, MJ Lorenzo, L Cacicedo, RM Tolon, JA Balsa, J Lopez-Fernandez and F Sanchez-Franco
Servicio de Endocrinologia, Fundacion Jimenez Diaz, Madrid, Spain.

The effects of recombinant human insulin-like growth factor I (IGF-I) on both vasoactive intestinal peptide (VIP) and PRL production and gene expression were studied using rat anterior pituitary cell cultures grown in serum-free defined medium. We also examined whether pituitary VIP could be involved in the PRL response to IGF-I and hence in a paracrine regulatory system. Exposure of cultured anterior pituitary cells to IGF-I (2.6 nM) for 3 h caused a significant decrease in both VIP content and media PRL. Treatment with IGF-I (from 0.65-5.2 nM) for 48 h increased VIP production and VIP messenger RNA (mRNA) accumulation, whereas only an increase in media and intracellular PRL content without changes in mRNA was observed. In all these experiments, IGF-I led to a decrease in both GH secretion and expression. Immunoglobulins G purified from VIP antiserum inhibited IGF-I-induced PRL release without affecting intracellular and mRNA levels. The inhibition of both GH secretion and gene expression induced by IGF-I was not blocked by VIP antiserum. In conclusion, these results indicate that IGF-I induces VIP gene expression, and its secretion and also increases PRL secretion. The effect of IGF-I on PRL release is specifically mediated by VIP through a paracrine or autocrine mechanism.

This article has been cited by other articles:

				D. Romano, M. Pertuit, R. Rasolonjanahary, J.-V. Barnier, K. Magalon, A. Enjalbert, and C. Gerard Regulation of the RAP1/RAF-1/Extracellularly Regulated Kinase-1/2 Cascade and Prolactin Release by the Phosphoinositide 3-Kinase/AKT Pathway in Pituitary Cells Endocrinology, December 1, 2006; 147(12): 6036 - 6045. [Abstract] [Full Text] [PDF]

				M Fernandez, F Sanchez-Franco, N Palacios, I Sanchez, and L Cacicedo IGF-I and vasoactive intestinal peptide (VIP) regulate cAMP-response element-binding protein (CREB)-dependent transcription via the mitogen-activated protein kinase (MAPK) pathway in pituitary cells: requirement of Rap1 J. Mol. Endocrinol., June 1, 2005; 34(3): 699 - 712. [Abstract] [Full Text] [PDF]

				M. Delgado, D. Pozo, and D. Ganea The Significance of Vasoactive Intestinal Peptide in Immunomodulation Pharmacol. Rev., June 1, 2004; 56(2): 249 - 290. [Abstract] [Full Text] [PDF]

				O. Gomez and J. A. Balsa Autocrine/Paracrine Action of Pituitary Vasoactive Intestinal Peptide on Lactotroph Hyperplasia Induced by Estrogen Endocrinology, October 1, 2003; 144(10): 4403 - 4409. [Abstract] [Full Text] [PDF]

				J. Schwartz Intercellular Communication in the Anterior Pituitary Endocr. Rev., October 1, 2000; 21(5): 488 - 513. [Abstract] [Full Text]

				S. Fruchtman, L. Jackson, and R. Borski Insulin-Like Growth Factor I Disparately Regulates Prolactin and Growth Hormone Synthesis and Secretion: Studies Using the Teleost Pituitary Model Endocrinology, August 1, 2000; 141(8): 2886 - 2894. [Abstract] [Full Text] [PDF]

				T. Iwasaka, S. Umemura, K. Kakimoto, H. Koizumi, and Y. R. Osamura Expression of Prolactin mRNA in Rat Mammary Gland During Pregnancy and Lactation J. Histochem. Cytochem., March 1, 2000; 48(3): 389 - 396. [Abstract] [Full Text]

				L. Stefaneanu, L. Powell-Braxton, W. Won, V. Chandrashekar, and A. Bartke Somatotroph and Lactotroph Changes in the Adenohypophyses of Mice with Disrupted Insulin-Like Growth Factor I Gene Endocrinology, September 1, 1999; 140(9): 3881 - 3889. [Abstract] [Full Text]