Plasma Growth Hormone and Slow Wave Sleep Increase After Interruption of Sleep

Abstract

A comparison was made of plasma hGH and of sleep stages during one night of undistrubed sleep and one night in which sleep was interupted by an hour of enforced wakefulness folowing the end of the second NREM-REM sleep cycle in 8 normal subjects. Plasma was sampled at 15-min intervals. HGH and slow wave sleep were both significantly increased in the two cycles immediately following the period awake compared with the same two cycles during nights of uninterruped sleep. The difference arose predominantly in the fourth cycle of the night, i.e., in the second cycle after the sleep interuption. The findings are consistent with the belief that extra wakefulness brings additional sleep of high RESTORATIVE properties.

Relationship of Plasma Growth Hormone to Slow-Wave Sleep in African Sleeping Sickness

“…P3) where the circadian rhythms of the sleep-wake cycle, cor tisol and prolactin are totally disrupted [13,14] and SWS episodes are distributed throughout the total day-night cycle [13]. Thus, the association between SWS and GH secretion remains consistent even under the conditions of our sleeping sickness model supporting the hypothesis of an involvement of GH or GHRH in sleep regulation [16,17], Although dissociations between sleep and GH secre tion have been described [4,[6][7][8], sleep and stimulation of GH secretion are regarded as outputs of a common cen tral nervous system mechanism [1,17] with hypothalamic GHRH being the likely factor for synchronizing GH secretion and SWS [12]. GHRH has the capacity for pro moting sleep and releasing GH from the pituitary [16,18].…”

“…The well-known temporal relationship between sleep and growth hormone (GH), specifically with slow-wave sleep (stages 3 and 4, SWS), is constant from night to night in a given subject [1][2][3], is recurrent after sleep interrup tion and remains associated with sleep when sleep onset is delayed [3], when the sleep-wake cycle is reversed by 12 h [2], or in the jet lag model [4], However, later studies have questioned the apparent dependency of GH release on the occurrence of SWS [5,6], Dissociations between GH peaks and SWS have been found under unusual sleeping conditions [4,7,8] and even under normal sleep-wake conditions [9], and in a variety of syndromes as acromegaly [10] and narcolepsy [11], It has been suggested that SWS and GH are not causally related, but two independent outputs of a com mon hypothalamic growth hormone-releasing hormone (GHRH) mechanism [1,12] A recent detailed pulse-by-pulse analysis of plasma GH levels and the pituitary secretion of GH during sleep [5] showed that GH secretion rates are 4-fold higher during SWS compared to wakefulness, stages 1 and 2, and rapideye movement (REM) sleep. Furthermore, maximal cor relations between SWS and plasma GH occurred when plasma levels of GH lagged EEG data by 16 min.…”

Circadian system, sleep and endocrinology

“…Indeed, growth hormone levels are increased during sleep, with the major increase occurring soon after sleep onset, irrespective of the time of day that sleep takes place (Honda et al, 1969; Born et al, 1988; Pietrowsky et al, 1994; Weibel et al, 1997). When an individual’s nocturnal sleep is interrupted, a growth hormone surge occurs fairly soon after recommencement of sleep (Beck et al, 1975). Growth hormone surges can occur multiple times during a sleep period (Takahashi et al, 1968; Van Cauter et al, 1992).…”

Endocrine and metabolic changes during sleep

“…GH secretion appears to be sleep-dependent and is suppressed during sleep deprivation (Sassin et al, 1969;Beck et al, 1975). However, in sleep-deprived but relaxed normal young males in a supine position an unchanged nocturnal GH peak is observed (Mullington et al, 1996).…”