The pathologic effects of sex steroids on the hypothalamic arcuate nucleus of adult rats were examined using numbers of reactive microglia and astrocytic granules as quantitative indices of neuropathology. / Microglial and astrocytic reactions were observed in adult female rats entering a state of "persistent estrus" following a single injection of 2 mg estradiol valerate (EV) or exposure to continuous illumination. Lower doses of EV failed to elicit both the persistent estrus state and significant glial responses. In EV-treated animals, a hypothalamic lesion could be prevented by prior ovariectomy or by pituitary-ovarian suppression with medroxyprogesterone acetate indicating that an ovarian factor is responsible for the neuropathological changes. This ovarian product is probably estradiol since dose-related enhancement of glial reactivity occurs in male rats treated with multiple injections of EV. / Arcuate pathology developed spontaneously in "senile persistent estrus" female and aging male rats. In females, but not in males, early gonadectomy suppressed age-related arcuate glial reactivity. Conceivably, estrogen withdrawal or EV-treatment respectively retards or accelerates histologic aging of the female gonadotropic hypothalamus. / Testosterone treatment occasionally elicited mild arcuate glial responses, possibly through prior aromatization to estradiol. In contrast, 5 (alpha)-dihydrotestosterone (a non-aromatizable androgen) appeared to suppress astrocytic granule counts below control values. / The EV-induced persistent estrus rat may serve as a useful model for Clover disease of the ewe and the human polycystic ovarian syndrome.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.77140 |
| Date | January 1982 |
| Creators | Schipper, Hyman M. |
| Contributors | Brawer, James (Supervisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Anatomy and Cell Biology) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000139415, proquestno: AAINK58057, Theses scanned by UMI/ProQuest. |
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