Evidence of proceptive without receptive defeminization in male ferrets.
The latencies of groups of gonadectomized male and female ferrets to approach and interact with a sexually active stimulus male were measured after administration of estradiol benzoate (EB; 0, 5, 10, or 15 micrograms/kg) in adulthood. Receptive responsiveness to stud males was also assessed in these same ferrets during additional tests. Control female ferrets gonadectomized on Postnatal Day 35 displayed a dose-dependent reduction in approach latencies to the stud male which did not occur in control males castrated on Day 35. The approach latencies of males castrated on Postnatal Day 20 or Day 5 were intermediate between these two extremes. Equivalent dose-dependent reductions in approach latencies were observed in groups of ferrets ovariectomized on Day 5 and implanted sc with Silastic capsules containing either no hormone or different doses of testosterone over Postnatal Days 5-20 or 20-35. Equivalent dose-dependent increments in acceptance quotients were obtained in all groups of male and female ferrets following EB treatment. These results suggest that the capacity to display the proceptive, or appetitive, components of feminine sexual behavior is normally reduced in male ferrets as a consequence of the perinatal action of testicular hormones whereas receptive behavioral capacity is retained in males of this species.