Effect of hypophysectomy on immunocytochemically demonstrated gonadotropin-releasing hormone in the rat brain.

The objective was to determine the effect of hypophysectomy on the store of gonadotropin-releasing hormone (GnRH) in certain parts of the brain as revealed by immunocytochemistry. The antiserum used was prepared against synthetic GnRH conjugated with limpet hemocyanin. No change was observed in the store of GnRH in the organum vasculosum of the lamina terminalis or in the cephalic segment of the median eminence GnRH was depleted severely from the central and caudal (junction with the infundibular stem) segments of the median eminence. GnRH was not found in the axons of magnocellular neurons that regenerate during repair of the median eminence-pituitary stalk after hypophysectomy.