Anterior hypothalamic lesions and pubertal development in female rhesus monkeys

Electrolytic lesions were made in the anterior hypothalamus of 8 prepubertal female rhesus monkeys, aged 1.1-1.7 years. Six unoperated females served as controls. No effects were found of the lesions upon age and body weight at menarche or at first ovulation, as estimated by blood levels of progesterone and laparoscopic observations. From these findings it appears that the neural control of puberty in the female rhesus may not be exerted through the anterior hypothalamus, in contrast with the rat and ferret. Further, an attempt was made to identify biometric correlates of hormonal changes during puberty. Firstly, the well known dip in growth rate, about 0.4 years before menarche, was observed. Secondly, there was a marked spurt in growth of the nipples starting at 0.2 years before menarche. The close temporal association between accelerated nipple growth and menarche suggests that both of these developmental characteristics result from changes in (presumably ovarian) steroid hormone secretion.