Decreased testosterone levels and accelerated extinction of a conditioned taste aversion in fluid-deprived male rats.

The hypothesis that fluid deprivation accelerates extinction of a conditioned taste aversion in male Sprague-Dawley-derived rats by reducing serum testosterone levels was tested. Serum testosterone levels were found to be lower in fluid-deprived males than in nondeprived males (Experiments 1 and 2). Exogenous testosterone treatment that results in high physiological levels of serum testosterone slowed the extinction of fluid-deprived gonadectomized males to rates comparable with those of nondeprived sham males (Experiment 3). It was noted, however, that testosterone treatment was less effective in slowing extinction in fluid-deprived gonadectomized males than in nondeprived gonadectomized males even though the serum testosterone levels were the same (Experiments 3 and 4). These results provide strong support for the original hypothesis, but they suggest that fluid deprivation also reduces sensitivity to testosterone.