Reproductive strategies in males and females

© 1998 Journals of Reproduction and Fertility 1359-6004/98 $12.50 Puberty, the transition from a sexually immature state to one of full reproductive activity, is timed by signals acting in the brain to increase activity of the hypothalamo–pituitary axis which stimulates the production of mature gametes. There are profound sex differences in the timing of puberty in many species. This occurs by sexual differentiation of the neuroendocrine control of pituitary gonadotrophin secretion. Studies using sheep as an experimental model have defined some of the factors responsible for this developmental difference in reproductive neuroendocrine function. We have studied the prenatal organizers (prenatal steroids), postnatal cues (growth and photoperiod responses) and the effectors (GnRH neurones) that time the pubertal process. Our experimental strategy has been to conduct complementary anatomical and physiological investigations to link form and function in the sexual differentiation of reproductive neuroendocrine function.