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Biol Reprod

Title:		The consequences of altered somatotropic system on reproduction
Author(s):		Chandrashekar V; Zaczek D; Bartke A;
Address:		"Department of Physiology, Southern Illinois University School of Medicine, Carbondale, Illinois 62901, USA. shekar@siu.edu"
Journal Title:		Biol Reprod
Year:		2004
Volume:		20040317
Issue:		1
Page Number:		17 - 27
DOI:		10.1095/biolreprod.103.027060
ISSN/ISBN:		0006-3363 (Print) 0006-3363 (Linking)
Abstract:		"Although the primary control of gonadotropin secretion is by the hypothalamic GnRH and the gonadal function is controlled by the pituitary gonadotropins and prolactin, the emerging evidence suggests a vital role of the somatotropic axis, growth hormone (GH), and insulin-like growth factor-I (IGF-I) in the control of the pituitary and gonadal functions. It has been shown that GH deficiency, GH resistance, and experimental alterations in IGF-I secretion modify folliculogenesis, ovarian maturation, ovulation, and pregnancy, and in the male, GH/IGF-I plays an important role in spermatogenesis and the Leydig cell function. The primary focus of this review is to examine the role of GH/ IGF-I on the onset of puberty, fertility, pituitary, and gonadal endocrine functions. A number of studies have revealed that fertility is affected in GH-deficient dwarf and in IGF-I gene-ablated mice, possibly due to subnormal function of either the pituitary gland or the gonads. In the female GH receptor gene knockout (GHR-KO) mice, there was impairment in follicular development, ovulation rate, sexual maturation, production of and responsiveness to pheromonal signals, and the corpus luteum function. In IGF-I-deficient male GHR-KO mice, puberty is delayed, spermatogenesis is affected, and neuroendocrine-gonadal function is attenuated. Similarly, in some of the human Laron syndrome patients, puberty is delayed due to GH resistance. These data suggest that, in addition to GnRH and gonadotropins, GH/IGF-I influences the pituitary and gonadal functions in animals and humans"
Keywords:		Animals Growth Hormone/*physiology Humans Insulin-Like Growth Factor I/*physiology Reproduction/*physiology;
Notes:		"MedlineChandrashekar, Varadaraj Zaczek, Denise Bartke, Andrzej eng HD-37672/HD/NICHD NIH HHS/ HD-37950/HD/NICHD NIH HHS/ Research Support, U.S. Gov't, P.H.S. Review 2004/03/19 Biol Reprod. 2004 Jul; 71(1):17-27. doi: 10.1095/biolreprod.103.027060. Epub 2004 Mar 17"