OVERNIGHT HUMAN PLASMA MELATONIN, CORTISOL, PROLACTIN, TSH, UNDER CONDITIONS OF NORMAL SLEEP, SLEEP-DEPRIVATION, AND SLEEP RECOVERY

Early investigations of the effect of sleep deprivation on plasma mela tonin reported no major changes, Recently, 36 hrs of sleep deprivation was reported To elevate melatonin levels on the post-sleep deprivatio n night. Given these contradictions melatonin, cortisol, prolactin, an d thyroid stimulating hormone before, during, and, after sleep depriva tion were examined in nine healthy young males following one night of sleep deprivation. Hormone levels at hourly intervals, for each night, were statistically analyzed by a repeated measures, two-way factorial ANOVA. ANOVA was also performed for measures of area under the curve (AUC), No significant differences were observed for melatonin levels. Cortisol was significantly higher on the sleep deprivation night presu mably reflecting the aroused state accompanying being awake; however, there were several time points on the control night when it was elevat ed also. Prolactin was higher on the post-sleep deprivation and contro l nights but did not rise on the deprivation night, indicating a usefu l nonpolysomnographic index for discriminating overnight sleep and awa ke states. TSH levels showed a similar rise during the control and sle ep deprivation nights, but remained flat on the post-sleep deprivation night, It appears that the pineal is insulated against feedback from changes to the level of arousal accompanying sleep and wakefulness. In comparison, cortisol, prolactin, and TSH levels vary with these state s and are, therefore, useful indices of arousal and sleep-wake.