Effects of photoperiod on hypothalamic luteinizing hormone releasing hormone in the male hamster

G. E. Pickard, A. J. Silverman

Research output: Contribution to journalArticle

72 Scopus citations

Abstract

Male hamsters were maintained on long (14 h light : 10 h darkness; 14L:10D) or short (6L:18D) photoperiods. Animals on short-days had reduced levels of LH in the serum and anterior pituitary gland, decreased androgen in the circulation and regressed testes and accessory sex organs. These same hamsters had significantly raised concentrations of hypothalamic luteinizing hormone releasing hormone (LH-RH). There was no significant difference in the response to exogenous LH-RH between groups maintained on long- and short-days. Castration significantly reduced levels of LH-RH in the hypothalamus in the long-day animals but had little effect on this parameter in short-day animals which had already undergone testicular regression. The increased levels of LH-RH in the hypothalami of both intact and castrated hamsters on non-stimulatory photoperiods is interpreted as a decreased release of the neurohormone which subsequently results in a decreased release of LH.

Original languageEnglish (US)
Pages (from-to)421-428
Number of pages8
JournalJournal of Endocrinology
Volume83
Issue number3
DOIs
StatePublished - 1979

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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