Age-related deficits in brain androgen binding and metabolism, testosterone, and sexual behavior of male rats

Kathleen C. Chambers, Janice E. Thornton, Charles E. Roselli

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54 Scopus citations


Brain androgen binding and metabolism, serum testosterone (T), and sexual behavior were measured in old and young male Fischer 344 rats. After completion of sexual behavior tests, blood was collected for T assay and brains were removed for simultaneous measurements of cytosolic (ARc) and nuclear (ARn) androgen receptors and aromatase activity (AA) in the preoptic area (POA), hypothalamus (HYP) and amygdala (AMG). In Experiment 1, old and young intact males were examined. None of the old males ejaculated in any of the tests of sexual behavior whereas all of the young males ejaculated. The old males had lower levels of serum T, lower levels of ARn in the POA and HYP and lower levels of AA in the POA. The ARc levels of the old and young males did not differ. Experiment 2 was designed to determine if the deficits in brain androgen binding and metabolism were due to low levels of T. Old and young T-treated gonadectomized (GX-T) males and young intact (I) males were examined. T levels were comparable in the young and old GX-T males and were higher in each of these groups than in the young I males. In sexual behavior tests, all of the young but only 25% of the old GX-T males ejaculated. Although ARn levels in the old GX-T males were lower than in the young GX-T males, they were comparable to the young I male levels. No age-related differences in T induction of AA were observed. These data suggest that there is an association between decreased T levels in old males and decreased ARn and AA levels but no association between decreased T and decreased sexual behavior. Thus the age-related deficits in behavior are probably not due to changes in ARn and AA.

Original languageEnglish (US)
Pages (from-to)123-130
Number of pages8
JournalNeurobiology of Aging
Issue number2
StatePublished - 1991


  • Aged male rats
  • Amygdala
  • Aromatase activity
  • Cytosolic androgen receptors
  • Hypothalamus
  • Nuclear androgen receptors
  • Preoptic area
  • Serum testosterone
  • Sexual behavior

ASJC Scopus subject areas

  • Neuroscience(all)
  • Aging
  • Clinical Neurology
  • Developmental Biology
  • Geriatrics and Gerontology


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