Asynchrony of the reproductive organs of the male vespertilionid bat, Scotophilus heathi: role of gonadotrophins

Changes in the LK-cells of the anterior pituitary in relation to the reprod uctive cycle in the male Scotophilus heathi (Horsfield, 1831) are described . Immunocytochemical studies of the pituitary suggested two annual peaks of LH accumulation and release each associated with a period of active sperma togenesis and testosterone secretion. Further, in vitro study showed differ ences in testicular responsiveness to LH stimulation during November (a per iod of active spermatogenesis) and December (winter dormancy). Present stud y further showed that FSH is also capable of stimulating androgen secretion from the testis. Testicular FSH responsiveness varies from recrudescence t o winter dormancy and this may be responsible for maintaining high circulat ing androstenedione production in S. heathi during this period.