Growth hormone (GH ) cells may augment or influence gonadotropes during the estrous cycle to enhance fertility. Transitory cells with GH antigens that express LH and FSH-beta subunit mRNAs and antigens (in the same or separate storage granules) appear just before ovulation. Furthermore, they also bind analogs of gonadotropin releasing hormone (GnRH) and growth hormone releasing hormone (GHRH). These cells may be transitional somatogonadotropes that function to support ovulation. The hypothesis for aim 1 is that somatogonadotropes will express GH or prolactin mRNA and Pit-1 transcription factors and gonadotropin antigens during late diestrus and early proestrus. Furthermore, this expression may be stimulated by exposing cells from diestrous rats to estradiol, activin and/or GnRH. The somatogonadotropes will be detected by in situ hybridization for GH, Pit-1, LH, or FSH beta mRNAs followed by immunolabeling for the gonadotropin antigens. The second group of studies (Aim 2) will test the hypothesis that the transitional somatogonadotropes from proestrus rats can secrete LH or FSH. The assays will include the reverse hemolytic plaque assays, cell dot blot assays, and radioimmunoassays. Secretagogues for gonadotropes and somatotropes will also be used to learn if they affect secretion.
Aim 3 studies will test the hypothesis that somatogonadotropes will increase expression of mRNA for GnRH receptors during diestrus and will maintain their ability to bind GHRH. This binding will be detected by affinity cytochemical protocols which use biotinylated analogs of the ligands to label target cells. Alternatively, GH may be present in gonadotropes as a regulatory molecule. Thus, aim 4 will test the hypothesis that GH may mediate gonadotrope functions during proestrus. Effects of exogenous and endogenous GH on gonadotropin secretion, storage, and synthesis will be tested. GH is now considered a co-gonadotropin because of its ability to enhance fertility in some patients. These studies will elucidate role(s) for GH during ovulation in the pituitary.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD033915-02
Application #
2403573
Study Section
Reproductive Endocrinology Study Section (REN)
Project Start
1996-08-01
Project End
2000-07-31
Budget Start
1997-08-01
Budget End
1998-07-31
Support Year
2
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Texas Medical Br Galveston
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
041367053
City
Galveston
State
TX
Country
United States
Zip Code
77555
Odle, Angela; Allensworth-James, Melody; Childs, Gwen V (2018) The War on the Placenta: The Differing Battles of High-Fat Diet and Obesity. Endocrinology 159:1642-1643
Childs, Gwen V; Iruthayanathan, Mary; Akhter, Noor et al. (2006) Estrogen mediated cross talk between the ovary and pituitary somatotrope. Pre-ovulatory support for reproductive activity. Mol Cell Endocrinol 247:60-3
Iruthayanathan, Mary; Zhou, Yi-Hong; Childs, Gwen V (2005) Dehydroepiandrosterone restoration of growth hormone gene expression in aging female rats, in vivo and in vitro: evidence for actions via estrogen receptors. Endocrinology 146:5176-87
Childs, Gwen V; Iruthayanathan, Mary; Akhter, Noor et al. (2005) Bipotential effects of estrogen on growth hormone synthesis and storage in vitro. Endocrinology 146:1780-8
McDuffie, Iris A; Akhter, Noor; Childs, Gwen V (2004) Regulation of leptin mRNA and protein expression in pituitary somatotropes. J Histochem Cytochem 52:263-73
Childs, G V (2002) Development of gonadotropes may involve cyclic transdifferentiation of growth hormone cells. Arch Physiol Biochem 110:42-9
Childs, G V; Unabia, G (2001) The use of counterflow centrifugation to enrich gonadotropes and somatotropes. J Histochem Cytochem 49:663-4
Childs, G V; Armstrong, J (2001) Sites of epidermal growth factor synthesis and action in the pituitary: paracrine and autocrine interactions. Clin Exp Pharmacol Physiol 28:249-52
Childs, G V; Unabia, G; Komak, S (2001) Differential expression of estradiol receptors alpha and beta by gonadotropes during the estrous cycle. J Histochem Cytochem 49:665-6
Childs, G V; Unabia, G (2001) Epidermal growth factor and gonadotropin-releasing hormone stimulate proliferation of enriched population of gonadotropes. Endocrinology 142:847-53

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