• Animal Models;
  • Sex Steroid Replacement;
  • Pharmacologic Studies in Sexual Function;
  • Endocrinologic Studies of Sexual Function


Introduction.  Social stress induces sexual dysfunction and reduces serum testosterone (T) level in rats. Stressful events exert an influence on a variety of behaviors and physiology through hormonal changes. The mechanism of stress-induced sexual dysfunction is unknown.

Aim.  To investigate the role of dehydroepiandrosterone (DHEA) in copulatory behavior induced by social stress in rats.

Methods.  Stress-induced male rats were subjected to social stress in which the males lived in a wire-mesh siege located in a colony of male and female rats and were exposed daily to a brief defeat by the colony of males for five consecutive days. After the stress period, copulatory behavior and serum concentrations of DHEA and T were measured.

Main Outcome Measures.  The effects of DHEA, T, and NE-100, a selective sigma 1 receptor antagonist, on copulatory behavior following social stress were examined.

Results.  The males exhibited a marked suppression of copulatory behavior (elongation of intromission and ejaculation latencies). Serum concentrations of DHEA and T were significantly lower than those in nonstressed control males. Another three groups of social stressed males were injected daily with DHEA, T, or DHEA + NE-100 during the stress period. Injections of DHEA attenuated the stress-induced suppression of copulatory behavior, whereas T had no effect. The combined treatment of NE-100 made DHEA ineffective at restoring copulatory behavior.

Conclusions.  These results indicate that DHEA, but not its conversion to T, alleviates the suppressive effect of social stress on copulatory behavior via sigma 1 receptors. We suggest that the decreased endogenous DHEA is involved in copulatory disorders induced by social stress in rats. Mizuno T, Yotsuyanagi S, Nagasaka Y, and Namiki M. Dehydroepiandrosterone alleviates copulatory disorder induced by social stress in male rats. J Sex Med 2006;3:612–618.