Medial basal hypothalamic disconnection and the onset of puberty in the female rhesus monkey.

Abstract

Complete medial basal hypothalamic (MBH) disconnection was performed in four immature female rhesus monkeys to determine its effects on the maturation of the mechanisms that regulate gonadotropin secretion. The sexual development of these animals, as well as that of nine control monkeys of similar bone ages, was assessed by monitoring the stimulatory feedback actions of exogenous and endogenous estrogens on LH and FSH secretion. All neuronal inputs to the hypothalamus were transsected with a Halasz-type knife resulting in “islands” of MBH tissue comprising portions of the arcuate, ventromedial, suprachiasmatic, dorsomedial, paraventricular, and anterior and posterior hypothalamic nuclei. The disconnections produced deficits in neurohypophysial, adrenal, and thyroid secretory function, necessitating replacement with antidiuretic hormone, thyroxine, and cortisone. The postoperative administration of estradiol benzoate (42 μg/kg sc in oil) initially suppressed serum LH and FSH levels. During the 6th–8th post...