Further Studies on the Hormone Secretion of the Anterior Pituitary Transplanted Into the Hypophysiotrophic Area of the Rat Hypothalamus

Abstract

Anterior pituitary tissue was transplanted into different parts of the hypothalamus and other parts of the brain or under the renal capsule in hypophysectomized male and female rats. Hormone secretion by the grafted pituitary was assessed by evaluating the structure and function of the gonads, thyroids and adrenals 2-3 months after grafting. The state of the target glands depended entirely on the location of the pituitary transplant. If the pituitary was situated in the medial basal hypothalamus (the hypophysiotrophic area) gonadotrophic hormone secretion was nearly normal: the weight of the ovaries was normal and they contained ripe follicles and fresh corpora lutea; vaginal smears revealed the reappearance of nearly normal cycles after variable time intervals following hypophysectomy and pituitary transplantation; anterior hypothalamic lesions induced constant estrus, and compensatory hypertrophy of the ovary developed following unilateral ovariectomy. Direct contact with the capillary loops of the medi...