Cellular observations and hormonal correlates of feedback control of luteinizing hormone secretion by testosterone in long-term castrated male rhesus monkeys

J. A. Resko, A. C. Pereyra-Martinez, H. L. Stadelman, C. E. Roselli

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Testosterone at physiological levels cannot exert negative feedback action on LH secretion in long-term castrated male monkeys. The cellular basis of this refractoriness is unknown. To study it, we compared two groups of male rhesus macaques: One group (group 1, n = 4) was castrated and immediately treated with testosterone for 30 days; the second group (group 2, n = 4) was castrated and treated with testosterone for 9 days beginning 21 days after castration. Feedback control of LH by testosterone in group 1 was normal, whereas insensitivity to its action was found in group 2. Using the endpoints of concentrations of aromatase activity (P450(AROM) messenger RNA [mRNA]) and androgen receptor mRNA in the medial preoptic anterior hypothalamus and in the medial basal hypothalamus, we found that aromatase activity in both of these tissues was significantly low. er, P < 0.01, in group 2 compared with group 1 males. P450(AROM) mRNA and androgen receptor mRNA did not differ, however. Our data suggest that the cellular basis of testosterone insensitivity after long-term castration may reside in the reduced capacity of specific brain areas to aromatize testosterone. Because P450(AROM) mRNA did not change in group 2 males, we hypothesize that an estrogen-dependent neural deficit, not involving the regulation of the P450(AROM) mRNA, occurs in long-term castrated monkeys.

Original languageEnglish (US)
Pages (from-to)872-878
Number of pages7
JournalBiology of reproduction
Volume63
Issue number3
DOIs
StatePublished - Jan 1 2000

Keywords

  • Androgen receptor
  • Estradiol
  • Hypothalamus
  • LH
  • Leydig cells
  • Pituitary hormones
  • Steroid hormones
  • Testes
  • Testosterone

ASJC Scopus subject areas

  • Reproductive Medicine
  • Cell Biology

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