High dosage testosterone propionate induces copulatory behavior in the obese male Zucker rat.
Genetically obese male Zucker rats sire few litters compared with lean males. High dosage testosterone propionate (TP) dramatically improves their litter production. Here we report the effect of high dosage TP on the copulatory behavior of obese males. Subjects were placed with ovariectomized, hormonally-primed females 24 hr after receiving a subcutaneous injection of vehicle or 20 mg TP. Other obese males received three consecutive daily TP injections or TP once every three days for up to 30 days prior to being tested. While 90% of sham-injected lean males became sexually active, only 18.2% of sham-injected obese males did so. In contrast 50% to 62.5% of TP-injected obese males became active depending on TP exposure. The proportion of obese males which ejaculated was high for sham-injected males which copulated, but varied with TP exposure for TP-injected males. In other respects the copulatory performance of obese and lean males was similar. High dosage TP increases fertility by correcting a behavioral deficit. Three possible mechanisms of TP action are proposed.
Hemmes
R B
RB
Biology Department, Vassar College, Poughkeepsie, NY 12601.
Schoch
R
R
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003307:Copulation / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004542:Ejaculation / Q000187:drug effects; D008297:Male; D051381:Rats; D011924:Rats, Zucker; D012726:Sexual Behavior, Animal / Q000187:drug effects*; D013739:Testosterone / Q000494:pharmacology* / Q000502:physiology
D013739:Testosterone