Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man

Previous studies have indicated the existence of common mechanisms regulating sleep and somatotropic activity. In the present study, we investigated the effects of prolonged treatment with a novel, orally active, growth hormone secretagogue (MK-677) on sleep quality in healthy young and older adults. Eight young subjects (18-30 years) followed a double-blind, placebo-controlled, three-period crossover design. Each subject participated in three 7-day treatment periods (with bedtime drug administration), presented in random (Latin square) order, and separated by at least 14 days. Doses were 5 and 25 mg MK-677 and matching placebo. Six older subjects, ages 65-71 years, each participated in two 14-day treatment periods (with bedtime drug administration) separated by a 14-day washout. Doses were 2 and 25 mg MK-677 during the first and second periods, respectively. Baseline sleep and hormonal data were obtained on the 2 days preceding the beginning of the first 14-day treatment period. In young subjects, high-dose MK-677 treatment resulted in an approximately 50% increase in the duration of stage IV and in a more than 20% increase in REM sleep as compared to placebo (p < 0.05). The frequency of deviations from normal sleep decreased from 42% under placebo to 8% under high-dose MK-677 (p < 0.03). In older adults, treatment with MK-677 was associated with a nearly 50% increase in REM sleep (p < 0.05) and a decrease in REM latency (p < 0.02). The frequency of deviations from normal sleep also decreased (p < 0.02). The present findings suggest that MK-677 may simultaneously improve sleep quality and correct the relative hyposomato-tropism of senescence.