Circadian rhythm of serum testosterone and its relation to sleep: comparison with the variation in serum luteinizing hormone, prolactin, and cortisol in normal men.

Abstract

Frequent samples of blood were obtained for serum testosterone, LH, PRL, cortisol, and GH determinations in healthy men while awake and during nocturnal and daytime sleep. The results were correlated with polygraphic monitoring of the electroencephalogram, electrooculogram, and electromyogram. The mean serum levels of testosterone and PRL during nonrapid eye movement (NREM) sleep and rapid eye movement (REM) sleep differed significantly from those during the waking period. However, the mean levels of these hormones during REM sleep were not statistically different from those during NREM sleep. Through all states of waking and sleep, the mean level of LH remained unchanged. When the periods of nocturnal sleep were divided into four 3-h periods, namely 2000–2300 h (A), 2300–0200 h (B), 0200–0500 h (C), and 0500–0800 (D), testosterone was significantly increased during period D (P < 0.05). LH levels were similar in all four periods. The PRL level was significantly elevated during periods C (P < 0.01) and D (...