Persistent Link:
http://hdl.handle.net/10150/186910
Title:
Studies on inhibin in the Syrian hamster Mesocricetus auratus.
Author:
McAsey, Mary Ellen.
Issue Date:
1994
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Inhibin is a heterodimeric glycoprotein which may regulate FSH synthesis and secretion as well as follicular development and maturation. The source and physiological role of inhibin have not been established for the hamster, although several investigators have suggested that this hormone may function in the regulation of FSH in this species. The major objectives of these studies were to develop a radioimmunoassay (RIA) for the measurement of inhibin-a in hamster serum and tissue, to identify the primary source of inhibin and to examine the relationship between inhibin and FSH during postnatal development. A sensitive, accurate and specific RIA was developed and utilized to measure changes in circulating levels of inhibin-a following bilateral gonadectomy, in developing hamsters and in studies on inhibin throughout the estrous cycle. Circulating inhibin-a declined rapidly and significantly following bilateral gonadectomy in male and female hamsters suggesting a gonadal source. Serum FSH concentrations increased following the decline in serum inhibin-a levels. An inverse relationship between inhibin and FSH was observed in early postnatal development. Male hamsters exhibited high serum concentrations of inhibin-α and low concentrations of FSH prior to the third postnatal week. Young female hamsters exhibited low concentrations of circulating inhibin-α and early, high levels of FSH. With follicular stimulation prior to the first ovulation, ovarian and serum inhibin concentrations increased and serum FSH was suppressed suggesting a possible endocrine regulatory role for inhibin. Administration of PMSG to peripubertal female hamsters increased ovarian and serum levels of inhibin-α, and increased steady-state levels of inhibin subunit mRNAs. Elevated levels of immunoreactive inhibin-α in PMSG-treated hamsters were inversely correlated with serum FSH concentrations, providing evidence for the reciprocal relationship between inhibin and FSH. Immunoreactive inhibin-a increased gradually throughout diestrus in the hamster. Inhibin-α concentrations peaked in the circulation at the time of the preovulatory gonadotropin surge, then declined to a nadir on the morning of estrus. Significant reductions in serum concentrations of inhibin-α during early estrus may moderate the amount and duration of the secondary FSH rise and thus contribute to the regulation of follicle recruitment.
Type:
text; Dissertation-Reproduction (electronic)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Cell Biology and Anatomy; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Benson, Bryant

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleStudies on inhibin in the Syrian hamster Mesocricetus auratus.en_US
dc.creatorMcAsey, Mary Ellen.en_US
dc.contributor.authorMcAsey, Mary Ellen.en_US
dc.date.issued1994en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractInhibin is a heterodimeric glycoprotein which may regulate FSH synthesis and secretion as well as follicular development and maturation. The source and physiological role of inhibin have not been established for the hamster, although several investigators have suggested that this hormone may function in the regulation of FSH in this species. The major objectives of these studies were to develop a radioimmunoassay (RIA) for the measurement of inhibin-a in hamster serum and tissue, to identify the primary source of inhibin and to examine the relationship between inhibin and FSH during postnatal development. A sensitive, accurate and specific RIA was developed and utilized to measure changes in circulating levels of inhibin-a following bilateral gonadectomy, in developing hamsters and in studies on inhibin throughout the estrous cycle. Circulating inhibin-a declined rapidly and significantly following bilateral gonadectomy in male and female hamsters suggesting a gonadal source. Serum FSH concentrations increased following the decline in serum inhibin-a levels. An inverse relationship between inhibin and FSH was observed in early postnatal development. Male hamsters exhibited high serum concentrations of inhibin-α and low concentrations of FSH prior to the third postnatal week. Young female hamsters exhibited low concentrations of circulating inhibin-α and early, high levels of FSH. With follicular stimulation prior to the first ovulation, ovarian and serum inhibin concentrations increased and serum FSH was suppressed suggesting a possible endocrine regulatory role for inhibin. Administration of PMSG to peripubertal female hamsters increased ovarian and serum levels of inhibin-α, and increased steady-state levels of inhibin subunit mRNAs. Elevated levels of immunoreactive inhibin-α in PMSG-treated hamsters were inversely correlated with serum FSH concentrations, providing evidence for the reciprocal relationship between inhibin and FSH. Immunoreactive inhibin-a increased gradually throughout diestrus in the hamster. Inhibin-α concentrations peaked in the circulation at the time of the preovulatory gonadotropin surge, then declined to a nadir on the morning of estrus. Significant reductions in serum concentrations of inhibin-α during early estrus may moderate the amount and duration of the secondary FSH rise and thus contribute to the regulation of follicle recruitment.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineCell Biology and Anatomyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairBenson, Bryanten_US
dc.contributor.committeememberLeadem, Christopher A.en_US
dc.contributor.committeememberWilson, Jean M.en_US
dc.contributor.committeememberHoyer, Patricia B.en_US
dc.contributor.committeememberWise, Mark E.en_US
dc.identifier.proquest9517527en_US
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