Reduced Growth Hormone Secretion Prolongs Puberty But Does Not Delay the Developmental Increase in Luteinizing Hormone in the Absence of Gonadal

Previous studies have shown that the growth hormone (GH) axis is important for timing the later stages of puberty in female monkeys. However, it is not clear whether these growth-related signals are important for the initiation of puberty and early pu-bertal events. The present study, using female rhesus monkeys, used two approaches to answer this question. Experiment 1 test-ed the hypothesis that reduced GH secretion would blunt the rise in nocturnal LH secretion in young (17 mo; n 5 7) but not older adolescent ovariectomized females (29 mo; n 5 6). Re-duced GH secretion was induced by treating females with the sustained release somatostatin analogue formulation, Sandosta-tin LAR (625 mg/kg). Morning (0900–0930 h) and evening (2200–2230 h) concentrations of bioactive LH were higher in older adolescent compared to young adolescent females. How