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dc.contributor.advisorH. Maurice Goodman
dc.contributor.authorShamgochian, Maureen
dc.date2022-08-11T08:08:39.000
dc.date.accessioned2022-08-23T16:03:10Z
dc.date.available2022-08-23T16:03:10Z
dc.date.issued1990-05-01
dc.date.submitted2006-09-01
dc.identifier.doi10.13028/tyhs-8082
dc.identifier.urihttp://hdl.handle.net/20.500.14038/31424
dc.description.abstractThe observations that substance P (SP) is localized in the anterior pituitary gland (AP) and is regulated by the hormonal status of the animal, as well as the demonstration of SP binding sites in the AP, have led to the idea that SP may participate in the regulation of AP function. Numerous and sometimes contradictory reports of SP effects on AP hormone secretion, particularly on luteinizing hormone (LH), left the question of whether SP acts directly at the level of the AP to regulate LH secretion still unanswered. To investigate a possible physiological function of SP in the AP, the effects of exogenous SP on LH secretion from AP cells from adult and prepubertal male and female rats in short term culture were studied. It was found that SP (100nM-1μM) significantly stimulates LH release in cultured AP cells and that this effect varies as a function of age and sex. SP has no significant effect on LH release from AP cells of male and female prepubertal rats. After day 30 a sharp increase in the response to SP occurs in both sexes. This level of responsiveness continues through adulthood in AP cells from the female rat. In contrast, AP cells from male rats failed to respond during adulthood (over 50 days of age) but were highly responsive during the peripubertal period (30-35 days). The possibility that the responsiveness to SP is influenced by the endocrine status of the animal was investigated by exposing AP cells from responding animals to androgens in vivo and in vitro. It was found that AP cells from female rats treated with androgen were less responsive to 100nM SP but did respond at higher doses of SP. SP effects on AP function were further analyzed in experiments using radioligand binding assays to assess possible changes in SP receptor number or affinity as related to age and sex. In AP membranes from female rats, maximum binding is 8-fold higher (Bmax=4.2 pmo1/mg membrane protein) than in AP membranes from male rats (Bmax=560fmo1/ mg membrane protein). These studies suggest a role for SP as a secondary regulator of LH secretion with possible physiological significance for reproductive function.
dc.language.isoen_US
dc.rightsCopyright is held by the author, with all rights reserved.
dc.subjectPituitary Gland
dc.subjectAnterior
dc.subjectLuteinizing Hormone
dc.subjectSubstance P
dc.subjectAmino Acids, Peptides, and Proteins
dc.subjectBiological Factors
dc.subjectCells
dc.subjectEndocrine System
dc.subjectHormones, Hormone Substitutes, and Hormone Antagonists
dc.subjectNervous System
dc.titleThe Stimulation of Luteinizing Hormone Secretion from Anterior Pituitary Cells in Culture by Substance P: A Dissertation
dc.typeDoctoral Dissertation
dc.identifier.legacyfulltexthttps://escholarship.umassmed.edu/cgi/viewcontent.cgi?article=1129&context=gsbs_diss&unstamped=1
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/gsbs_diss/129
dc.legacy.embargo2017-04-24T00:00:00-07:00
dc.identifier.contextkey201317
refterms.dateFOA2022-08-24T06:38:35Z
html.description.abstract<p>The observations that substance P (SP) is localized in the anterior pituitary gland (AP) and is regulated by the hormonal status of the animal, as well as the demonstration of SP binding sites in the AP, have led to the idea that SP may participate in the regulation of AP function. Numerous and sometimes contradictory reports of SP effects on AP hormone secretion, particularly on luteinizing hormone (LH), left the question of whether SP acts directly at the level of the AP to regulate LH secretion still unanswered. To investigate a possible physiological function of SP in the AP, the effects of exogenous SP on LH secretion from AP cells from adult and prepubertal male and female rats in short term culture were studied. It was found that SP (100nM-1μM) significantly stimulates LH release in cultured AP cells and that this effect varies as a function of age and sex. SP has no significant effect on LH release from AP cells of male and female prepubertal rats. After day 30 a sharp increase in the response to SP occurs in both sexes. This level of responsiveness continues through adulthood in AP cells from the female rat. In contrast, AP cells from male rats failed to respond during adulthood (over 50 days of age) but were highly responsive during the peripubertal period (30-35 days). The possibility that the responsiveness to SP is influenced by the endocrine status of the animal was investigated by exposing AP cells from responding animals to androgens in vivo and in vitro. It was found that AP cells from female rats treated with androgen were less responsive to 100nM SP but did respond at higher doses of SP. SP effects on AP function were further analyzed in experiments using radioligand binding assays to assess possible changes in SP receptor number or affinity as related to age and sex. In AP membranes from female rats, maximum binding is 8-fold higher (Bmax=4.2 pmo1/mg membrane protein) than in AP membranes from male rats (Bmax=560fmo1/ mg membrane protein). These studies suggest a role for SP as a secondary regulator of LH secretion with possible physiological significance for reproductive function.</p>
dc.identifier.submissionpathgsbs_diss/129
dc.contributor.departmentMicrobiology and Physiological Systems
dc.description.thesisprogramCell Biology


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