Maturation of ovarian function in female ferrets is influenced by photoperiod

Sexual maturation of immature ferrets in response to a stimulatory photoperiod generally occurs within 6-7 weeks after imposition of long days at 16 weeks of age. In this study, females were examined for evidence of ovarian maturation after 22 days of exposure to the stimulatory photoperiod, before any sign of sexual maturation. The photoperiod-stimulated and control females were the same age (19 weeks), had similar body weights, and showed no evidence of vulvar oedema. Comparison of oestradiol secretory response to hCG stimulation and of follicular development in the ovary revealed marked ovarian stimulation in females kept in long days compared to control females kept in short days. A prolonged period of ovarian stimulation therefore occurs during exposure to long days before there is external evidence of sexual maturation in ferrets.