Mating-induced alterations in the regulatory mechanisms of male rats

The effect of mating behavior on the regulatory mechanisms of male rats was investigated. Moderate levels of copulatory behavior (two ejaculations/week for 6 weeks) reduced body weight gain, and decreased food efficiency. Mating also affected carcass composition: it caused a decrease in fat content and a rise in nitrogen and water levels. The altered regulatory functions were observed in two age groups: 14-17-week- old male rats and 27-week- old male rats. Controls for the non-copulatory components of mating demonstrated the specificity of the copulation effects. The regulatory functions of the control groups (Social-Interaction, Voluntary-Exercise, and Novel-Cage) were similar to those of the sexually rested, Home-Cage group. These results demonstrate that a naturally occurring behavior, mating, significantly affects regulatory mechanisms in the male rat. Since growth and longevity have been shown to be interrelated, these findings support the hypothesis that copulation can affect aging.