Two inhibitors of FSH binding to receptor have been purified from porcine follicular fluid. There are distinct substances which have opposite effects on FSH responsive cells; one (a 58,000 MW protein) being stimulatory (FSH agonist), the other (a complex glycopeptide) inhibitory (FSH antagonist).
The specific aims of this project are: 1) to obtain sufficient quantities of highly purified inhibitors for chemical and biological study, 2) to chemically identify the two inhibitors, 3) to develop specific probes for use in studying the inhibitors, 4) to identify the mechanism of action of both inhibitors, and 5) to identify their cellular localization in vivo. Purification methods proposed are based on previous experience isolating both inhibitors from porcine follicular fluid, chemical composition studies of low MW inhibitor and antigenic characterization of high MW inhibitor. Mechanism of action studies include receptor binding, in vitro (Sertoli cell culture) and in vivo experiments designed to determine if these inhibitors interact with receptor for FSH per se, and, if so, whether or not the inhibitors interact with the same receptor epitopes involved in FSH binding. Synthetic peptide fragments of FSH beta subunit or high MW FSH binding inhibitor and antibodies against these synthetic peptides will be generated as specific probes to facilitate mechanism of action studies. Immunohistochemical studies will be used to localize the inhibitors in vivo. Long term goals include evaluation of the physiological significance of the inhibitors. These inhibitors may prove to represent local (paracrine/autocrine) regulators which act at the level of receptor action to modulate FSH control of gonadal function. Such action implies that physiological studies will be complicated by compensatory changes in local modulators as concentrations of any one factor are experimentally manipulated. Achieving the goals of the present proposal will facilitate this long term goal by providing information regarding the cellular localization of inhibitors and by developing specific probes. Data obtained by this project is expected to improve our understanding of FSH structure/function relationships. Furthermore, this project may lead to improved understanding of normal gonadal function (e.g., fertility). Since aberrant control of the biosynthesis of local regulators might underlie some forms of human infertility (e.g., hypergonadotropic hypogonadism), new insights into the etiology of these diseases may also be obtained.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
2R01HD019302-05A1
Application #
3316547
Study Section
Biochemical Endocrinology Study Section (BCE)
Project Start
1987-07-01
Project End
1993-05-31
Budget Start
1989-09-01
Budget End
1990-05-31
Support Year
5
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of Rochester
Department
Type
School of Medicine & Dentistry
DUNS #
208469486
City
Rochester
State
NY
Country
United States
Zip Code
14627
Christin-Maitre, S; Taylor, A E; Khoury, R H et al. (1996) Homologous in vitro bioassay for follicle-stimulating hormone (FSH) reveals increased FSH biological signal during the mid- to late luteal phase of the human menstrual cycle. J Clin Endocrinol Metab 81:2080-8
Sluss, P M; Lee, K; Mattox, J H et al. (1994) Estradiol and progesterone production by cultured granulosa cells cryopreserved from in vitro fertilization patients. Eur J Endocrinol 130:259-64
Sluss, P M; Gentile, D P; Ewing, J F et al. (1993) Multiple molecular weight forms of immunoreactive alpha-inhibin in human seminal plasma. J Clin Endocrinol Metab 76:476-83
Sluss, P M; Schneyer, A L (1992) Low molecular weight follicle-stimulating hormone receptor binding inhibitor in sera from premature ovarian failure patients. J Clin Endocrinol Metab 74:1242-6
Daugherty, R L; Cockett, A T; Schoen, S R et al. (1992) Suramin inhibits gonadotropin action in rat testis: implications for treatment of advanced prostate cancer. J Urol 147:727-32
Schneyer, A L; Sluss, P M; Whitcomb, R W et al. (1991) Precursors of alpha-inhibin modulate follicle-stimulating hormone receptor binding and biological activity. Endocrinology 129:1987-99
Sluss, P M; Ewing, J F; Schneyer, A L (1990) Phospholipase C-mediated release of low molecular weight follicle-stimulating hormone receptor-binding inhibitor from testis membranes. Biol Reprod 43:1026-31
Sluss, P M; Schneyer, A L; Cockett, A T et al. (1989) Identification of a potential FSH modulatory protein in human testis and seminal plasma. J Androl 10:386-92
Sluss, P M; Schneyer, A L; Andersen, T T et al. (1989) Purification and chemical composition of a low molecular weight follicle-stimulating hormone binding inhibitor from porcine follicular fluid. Biol Reprod 41:863-70
Sluss, P M; Branca, A A; Ford, J J et al. (1989) Purification, measurement, and tissue distribution of a dansyl-derivatized glycopeptide from low-molecular weight follicle-stimulating hormone-inhibitor-containing fractions of porcine follicular fluid. Biol Reprod 40:407-15

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