Abstract
In the preceding paper, it was shown that the rat became tolerant to some psychotropic drugs when blockage of the conditioned avoidance response was estimated as an index of tranquillizing activity (1). In the course of these studies, a statistically significant difference was obtained between male and female rats in the development of tolerance upon the repeated administration of chlordiazepoxide and thioridazine. The purpose of the present study was to determine whether sex hormones are primarily concerned with this apparent sex difference in the development of the drug tolerance.
