Effect Of Nerve Fibers On Gonadotropin Secretion In Rat Anterior Pituitary

It is well known that Harris prefer to the classical theory of hypothalamic humoral regulation of the mammalian anterior pituitary. According to this hypothesis, hormones secreted by the hypophysitropic neurons in the hypothalamus was released at the median eminence and carried down the portal vessels to the anterior pituitary to regulate the function of the gland cells. The gland cells of the anterior pituitary are not innervated directly by the nerve fibers. However, in recent decade, our research team found many evidences to support the direct innervation of the anterior pituitary. First, a substantial amounts of SP-, CGRP-immunoreactive nerve fibers and a small amounts of GAL-, TH-, ChAT- and GABA-immunoreactive nerve fibers were discovered in anterior pituitary by immunohistochemical method and were found to be distributed mainly around the gland cells, even in close proximity to these cells, in several mammalian species including human. Further electron microscopic study has demonstrated the existence of typical synaptic structure between the varicosities of the nerve fibers and the gland cells, verifying morphologically that nerve fibers could regulate the function...