Insulin, insulin-like growth factor I (IGF-I) and IGF-II enhance basal and gonadotrophin-releasing hormone-stimulated luteinizing hormone release from rat anterior pituitary cells in vitro

Department of Reproductive Medicine, University of California San Diego, La Jolla.

The role of insulin-like growth factor I (IGF-I) and IGF-II on luteinizing hormone (LH) release is still unclear. The present study was performed to investigate modifications of basal and gonadotrophin-releasing hormone (GnRH)-stimulated (10(-9) mol/l) LH release, induced by 4-h and a 24-h incubation with physiological doses of IGF-I (1, 5 and 10 nmol/l) and IGF-II (5, 10 and 15 nmol/l) in comparison with insulin (0.0017, 0.1722 and 1.722 nmol/l), from primary cultures of male rat anterior pituitary cells. Both during the 4-h and the 24-h incubation, basal and GnRH-stimulated LH release were increased by IGF-I, IGF-II and insulin in a dose-dependent fashion. Present data confirm insulin's capability of potentiating anterior pituitary LH release from dispersed rat anterior pituitary cells in vitro, and reveal similar effects for physiological doses of IGF-I and IGF-II.

This article has been cited by other articles:

				S.K. Blank, C.R. McCartney, and J.C. Marshall The origins and sequelae of abnormal neuroendocrine function in polycystic ovary syndrome Hum. Reprod. Update, July 1, 2006; 12(4): 351 - 361. [Abstract] [Full Text] [PDF]

				R. V. Mehta, K. S. Patel, M. S. Coffler, M. H. Dahan, R. Y. Yoo, J. S. Archer, P. J. Malcom, and R. J. Chang Luteinizing Hormone Secretion Is Not Influenced by Insulin Infusion in Women with Polycystic Ovary Syndrome Despite Improved Insulin Sensitivity during Pioglitazone Treatment J. Clin. Endocrinol. Metab., April 1, 2005; 90(4): 2136 - 2141. [Abstract] [Full Text] [PDF]

				A. Rose, P. Froment, V. Perrot, M. J. Quon, D. LeRoith, and J. Dupont The Luteinizing Hormone-releasing Hormone Inhibits the Anti-apoptotic Activity of Insulin-like Growth Factor-1 in Pituitary {alpha}T3 Cells by Protein Kinase C{alpha}-mediated Negative Regulation of Akt J. Biol. Chem., December 10, 2004; 279(50): 52500 - 52516. [Abstract] [Full Text] [PDF]

				K. Patel, M. S. Coffler, M. H. Dahan, R. Y. Yoo, M. A. Lawson, P. J. Malcom, and R. J. Chang Increased Luteinizing Hormone Secretion in Women with Polycystic Ovary Syndrome Is Unaltered by Prolonged Insulin Infusion J. Clin. Endocrinol. Metab., November 1, 2003; 88(11): 5456 - 5461. [Abstract] [Full Text] [PDF]

				D. Romualdi, M. Guido, M. Ciampelli, M. Giuliani, F. Leoni, C. Perri, and A. Lanzone Selective effects of pioglitazone on insulin and androgen abnormalities in normo- and hyperinsulinaemic obese patients with polycystic ovary syndrome Hum. Reprod., June 1, 2003; 18(6): 1210 - 1218. [Abstract] [Full Text] [PDF]

				A. Quesada and A. M. Etgen Functional Interactions between Estrogen and Insulin-Like Growth Factor-I in the Regulation of alpha 1B-Adrenoceptors and Female Reproductive Function J. Neurosci., March 15, 2002; 22(6): 2401 - 2408. [Abstract] [Full Text] [PDF]

				D. M. Baker, B. Davies, W. W. Dickhoff, and P. Swanson Insulin-Like Growth Factor I Increases Follicle-Stimulating Hormone (FSH) Content and Gonadotropin-Releasing Hormone-Stimulated FSH Release from Coho Salmon Pituitary Cells In Vitro Biol Reprod, September 1, 2000; 63(3): 865 - 871. [Abstract] [Full Text]

				L. Poretsky, N. A. Cataldo, Z. Rosenwaks, and L. C. Giudice The Insulin-Related Ovarian Regulatory System in Health and Disease Endocr. Rev., August 1, 1999; 20(4): 535 - 582. [Abstract] [Full Text] [PDF]

				C. Weil, F. Carré, O. Blaise, B. Breton, and P.-Y. Le Bail Differential Effect of Insulin-Like Growth Factor I on in Vitro Gonadotropin (I and II) and Growth Hormone Secretions in Rainbow Trout (Oncorhynchus mykiss) at Different Stages of the Reproductive Cycle Endocrinology, May 1, 1999; 140(5): 2054 - 2062. [Abstract] [Full Text]

				S. Zhen, M. Zakaria, A. Wolfe, and S. Radovick Regulation of Gonadotropin-Releasing Hormone (GnRH) Gene Expression by Insulin-Like Growth Factor I in a Cultured GnRH-Expressing Neuronal Cell Line Mol. Endocrinol., July 1, 1997; 11(8): 1145 - 1155. [Abstract] [Full Text]