FSH-Releasing Hormone and LH-Releasing Hormone

Publisher Summary This chapter discusses the role of follicle-stimulating hormone (FSH)-releasing hormone and luteinizing hormone (LH)-releasing hormone. The involvement of the anterior pituitary in process of reproduction began with the discovery of gonadotropic activity in the pituitary. FSH stimulates the growth of the ovarian follicle by promoting mitotic proliferation of the granulosa cells. The response to FSH is demonstrable by the presence of follicles in all stages of development, initiation of antrum formation, and increase in ovarian weight. FSH is a gametogenic hormone in the male; it affects the function and structure of seminiferous tubules and production of spermatozoa. In the hypophysectomized rat and in hypophysectomized humans, FSH, given together with LH, stimulates spermatogenesis. The presence of androgens is necessary for full spermatogenesis. LH is responsible for stimulation of steroidogenesis in the ovarian follicle and for ovulation in the ovary previously stimulated by FSH and the transformation of the graafian follicles into corpora lutea. After ovulation, under the influence of LH, some granulosa cells increase in size and undergo the process of luteinization.