Oral testosterone self-administration in male hamsters: dose-response, voluntary exercise, and individual differences.
Although testosterone was declared a controlled substance in 1990, the potential for steroid dependence is largely unexplored. The present study used food-induced drinking with oral testosterone self-administration in hamsters to determine (1) the dose-response for testosterone reward, (2) links between testosterone self-administration and voluntary exercise, and (3) factors predicting individual differences in androgen intake. Testosterone (1-4 mg/ml) was presented in aqueous solution 3 h/day for 35 days, with and without food. At 3 mg/ml, testosterone maintained fluid intake, even without food (3.0 +/- 0.2 ml/3h). At 4 mg/ml, fluid intake declined to 2.4 +/- 0.3 ml/3h in the presence of food. However, no dose-response relationship between testosterone self-administration and reward was observed. To test the interaction of testosterone and exercise, males drinking testosterone (RUN + T) or vehicle received a running wheel. Additional males self-administered testosterone without exercise. Testosterone intake correlated positively with exercise and negatively with body weight in RUN + T males. Experiment 3 determined the relationship between testosterone self-administration and mating or saccharin preference. There were no statistically significant correlations. However, testosterone self-administration increased mating behavior. These data demonstrate that testosterone is a mild reinforcer. Although preference for androgens is not predicted by mating or saccharin intake, testosterone intake is linked with voluntary exercise.
Wood
Ruth I
RI
Department of Cell and Neurobiology, Keck School of Medicine at the University of Southern California, Los Angeles 90033, USA. riw@usc.edu
D000284:Administration, Oral; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects; D003307:Copulation / Q000187:drug effects*; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004542:Ejaculation / Q000187:drug effects; D005518:Food Preferences; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D008297:Male; D008647:Mesocricetus; D009043:Motor Activity / Q000187:drug effects*; D010805:Physical Conditioning, Animal; D012201:Reward; D012439:Saccharin; D012646:Self Administration; D013739:Testosterone / Q000494:pharmacology*; D014836:Volition
D012739:Gonadal Steroid Hormones; D013739:Testosterone; D012439:Saccharin