EVIDENCE OF HYPOTHALAMIC CONTROL OF HYPOPHYSEAL GONADOTROPIC FUNCTIONS IN THE FEMALE GUINEA PIG1

Publisher Website
Google Scholar
Abstract
Marked gonadal changes occurred in 28 of 70 mature [female] guinea pigs after lesions were placed in the hypothalamus. Nineteen animals were unable postoperatively to secrete luteinizing hormone. The hormonal imbalance thus created resulted in marked ovarian follicular development and genital hypertrophy. The lesions * of this group of animals were large, bilateral and situated at the caudal end of the optic chiasma. Nine animals were acyclic postoperatively and showed marked genital atrophy. The lesions destroyed a major portion of the median eminence. Direct damage to the ant. lobe of the hypophysis occurred in only 1 animal. The lesions of the 42 remaining animals that showed normal estrous cycles postoperatively, destroyed various portions of the hypothalamus but in only 2 animals was there extensive damage to the median eminence and never was this structure completely destroyed. Lesions placed directly within the hypophysis abolished sexual cycles in only 2 of 14 operated animals even though as much as f of the hypophysis was destroyed. The lesions of the 2 exceptional animals destroyed the median eminence and neighboring hypothalamic structures inaddition to injuring the ant. lobe. The results of these expts. indicate that the hypothalamus and median eminence may be concerned in the regulation of pituitary gonadotrophic functions. It seems unlikely that they exert this control by nerve fibers that pass by way of the hypophyseal stalk.