Sexual behavior and testosterone in middle-aged male rats

G. D. Gray, E. R. Smith, Daniel Dorsa, J. M. Davidson

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

Various components of sexual behavior were compared in middle-aged (13 months) and young adult (3 months) male rats to ascertain the nature of behavioral differences and the role of testosterone (T) in these differences. Behavioral procedures included: 1) tests of mating behavior; 2) tests of mounting behavior with genital anesthetization that focused on sexual arousal; 3) tests of spontaneous seminal emission that focused on ejaculatory mechanisms. In Exp 1, sexually experienced or inexperienced middle-aged males showed evidence of reduced sexual arousal, with the inexperienced middle-aged group demonstrating the greatest reduction. The two middle-aged groups did not differ in plasma T levels, but both had levels significantly below those of the young group. In Exp 2, spontaneous seminal emission was found to occur more often in middle-aged retired breeders than in young sexually inexperienced males. In Exp 3, the dose-response relationship of behavior and T was evaluated in groups of castrated middle-aged and young males implanted with T-filled Silastic capsules of varying length. Before treatment, the middle-aged males evidenced lower sexual arousal (i.e. fewer positive tests and longer latency measures in mating tests and fewer mounts in mounting tests). After treatment, both age groups showed increased arousal with increasing T titer, but the middle-aged males remained lower than young males, even though T levels were equivalent between the age groups. Supraphysiological T sites titers did not increase the behavior of middle-aged males above the performance of untreated intact males. The results show that: 1) middle-aged male rats evidence a decline in sexual arousal but a slight increase in ejaculatory response; 2) the middle-aged decrease in circulating T is not the major factor in the decline of sexual arousal.

Original languageEnglish (US)
Pages (from-to)1597-1604
Number of pages8
JournalEndocrinology
Volume109
Issue number5
StatePublished - 1981
Externally publishedYes

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Sexual Behavior
Testosterone
Arousal
Age Groups
Capsules
Young Adult
Therapeutics

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

Gray, G. D., Smith, E. R., Dorsa, D., & Davidson, J. M. (1981). Sexual behavior and testosterone in middle-aged male rats. Endocrinology, 109(5), 1597-1604.

Sexual behavior and testosterone in middle-aged male rats. / Gray, G. D.; Smith, E. R.; Dorsa, Daniel; Davidson, J. M.

In: Endocrinology, Vol. 109, No. 5, 1981, p. 1597-1604.

Research output: Contribution to journalArticle

Gray, GD, Smith, ER, Dorsa, D & Davidson, JM 1981, 'Sexual behavior and testosterone in middle-aged male rats', Endocrinology, vol. 109, no. 5, pp. 1597-1604.
Gray GD, Smith ER, Dorsa D, Davidson JM. Sexual behavior and testosterone in middle-aged male rats. Endocrinology. 1981;109(5):1597-1604.
Gray, G. D. ; Smith, E. R. ; Dorsa, Daniel ; Davidson, J. M. / Sexual behavior and testosterone in middle-aged male rats. In: Endocrinology. 1981 ; Vol. 109, No. 5. pp. 1597-1604.
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