Abstract
Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) are mammalian
gonadotropins released from the anterior pituitary by Gonadotropin Releasing Hormone
(GnRH) in the hypothalamus. Various analogs ofGnRH have been identified. Localization of
these hormones is the first step in discovering the individual function of each analog.
Immunohistochemistry and confocal microscopy were used to localize Luteinizing Hormone
Releasing Hormone (LHRH), also known as mammalian GnRH, in the fetal bovine
hypothalamus. This analog is believed to differentiate the pituitary primordia during
embryonic development and initiate the release ofLH throughout the life of the animal.
Localization of LHRH bound to neuronal membranes began from embryonic day 100 of
gestation through term. Spatially neurons were located throughout the hypothalamus.
Specifically, LHRH neurons were identified in most of the tissue observed from the most
anterior sections including the OVL T and preoptic, rostral hypothalamus, extending as far
caudally as the medial mammillary nucleus and axons were observed in the median eminence
and ventral to the third ventricle.
