Effects of slow wave sleep deprivation on human growth hormone release in sleep: preliminary study

Acute Sleep Disruption Does Not Diminish Pulsatile Growth Hormone Secretion in Pubertal Children

Context

In children, growth hormone (GH) pulses occur after sleep onset in association with slow-wave sleep (SWS). There have been no studies in children to quantify the effect of disrupted sleep on GH secretion.

Objective

This study aimed to investigate the effect of acute sleep disruption on GH secretion in pubertal children.

Methods

Fourteen healthy individuals (aged 11.3-14.1 years) were randomly assigned to 2 overnight polysomnographic studies, 1 with and 1 without SWS disruption via auditory stimuli, with frequent blood sampling to measure GH.

Results

Auditory stimuli delivered during the disrupted sleep night caused a 40.0 ± 7.8% decrease in SWS. On SWS-disrupted sleep nights, the rate of GH pulses during N2 sleep was significantly lower than during SWS (IRR = 0.56; 95% CI, 0.32-0.97). There were no differences in GH pulse rates during the various sleep stages or wakefulness in disrupted compared with undisrupted sleep nights. SWS disruption had no effect on GH pulse amplitude and frequency or basal GH secretion.

Conclusion

In pubertal children, GH pulses were temporally associated with episodes of SWS. Acute disruption of sleep via auditory tones during SWS did not alter GH secretion. These results indicate that SWS may not be a direct stimulus of GH secretion.

Shaping the slow waves of sleep: A systematic and integrative review of sleep slow wave modulation in humans using non-invasive brain stimulation

The experimental study of electroencephalographic slow wave sleep (SWS) stretches over more than half a century and has corroborated its importance for basic physiological processes, such as brain plasticity, metabolism and immune system functioning. Alterations of SWS in aging or pathological conditions suggest that modulating SWS might constitute a window for clinically relevant interventions. This work provides a systematic and integrative review of SWS modulation through non-invasive brain stimulation in humans. A literature search using PubMed, conducted in May 2020, identified 3220 studies, of which 82 fulfilled inclusion criteria. Three approaches have been adopted to modulate the macro- and microstructure of SWS, namely auditory, transcranial electrical and transcranial magnetic stimulation. Our current knowledge about the modulatory mechanisms, the space of stimulation parameters and the physiological and behavioral effects are reported and evaluated. The integration of findings suggests that sleep slow wave modulation bears the potential to promote our understanding of the functions of SWS and to develop new treatments for conditions of disrupted SWS.

Circadian system, sleep and endocrinology

Levels of numerous hormones vary across the day and night. Such fluctuations are not only attributable to changes in sleep/wakefulness and other behaviors but also to a circadian timing system governed by the suprachiasmatic nucleus of the hypothalamus. Sleep has a strong effect on levels of some hormones such as growth hormone but little effect on others which are more strongly regulated by the circadian timing system (e.g., melatonin). Whereas the exact mechanisms through which sleep affects circulating hormonal levels are poorly understood, more is known about how the circadian timing system influences the secretion of hormones. The suprachiasmatic nucleus exerts its influence on hormones via neuronal and humoral signals but it is now also apparent that peripheral tissues contain circadian clock proteins, similar to those in the suprachiasmatic nucleus, that are also involved in hormone regulation. Under normal circumstances, behaviors and the circadian timing system are synchronized with an optimal phase relationship and consequently hormonal systems are exquisitely regulated. However, many individuals (e.g., shift-workers) frequently and/or chronically undergo circadian misalignment by desynchronizing their sleep/wake and fasting/feeding cycle from the circadian timing system. Recent experiments indicate that circadian misalignment has an adverse effect on metabolic and hormonal factors such as circulating glucose and insulin. Further research is needed to determine the underlying mechanisms that cause the negative effects induced by circadian misalignment. Such research could aid the development of novel countermeasures for circadian misalignment.

Growth hormone improves hippocampal adult cell survival and counteracts the inhibitory effect of prolonged sleep deprivation on cell proliferation

Sleep deprivation (SD) produces numerous deleterious changes in brain cells, including apoptosis. It has been demonstrated that growth hormone (GH) stimulates cell growth and counteracts apoptosis, although this anti-apoptotic effect has not been tested against SD. To determine the protective effect of GH administration on cell proliferation and survival in the dentate gyrus (DG) of the hippocampus after sleep deprivation; we injected Wistar adult rats with a low dose of recombinant human GH (rhGH 5 ng/kg) per seven days and then we gently sleep deprived the animals for 48 consecutive hours. 5-Bromodeoxiuridine (BrdU) was administered to assess cell proliferation after the GH treatment and NeuN was used as marker of cell fate. Our results indicate that GH produced a three fold increase in the number of BrdU positive cells within the DG [Control = 1044 ± 106.38 cells, rhGH = 2952 ± 99.84 cells, P<0.01]. In contrast, 48 h of SD significantly reduced cell proliferation but this effect was antagonized by the GH administration [SD = 540 ± 18.3 cells, rhGH + SD = 1116 ± 84.48 cells, P<0.004]. Paradoxically, SD and GH administration increased cell survival separately but no significantly compared with control animals. However, cell survival was increased in animals treated with rhGH+SD compared to rats injected with saline solution [P<0.04]. Within the survival cells, the percentage of neurons was higher in SD animals [95%] compared with saline group, while this percentage (NeuN positive cells) was increased in animals treated with rhGH+SD [120%] compared with rhGH [25%] alone. Our findings indicate that GH strongly promotes cell proliferation in the adult brain and also protects the hippocampal neuronal precursors against the deleterious effect of prolonged sleep loss.

EFFECT OF MULTI-FUNCTIONAL FABRIC ON SLEEP STAGES AND GROWTH HORMONE LEVELS DURING SLEEP

Nine young girls participated in cross-over sessions, sleeping with either multi-functional fabric (experimental session) or cotton (control session). The relative duration of slow-wave sleep (SWS) was 1.89-fold higher in the experimental session than in the control session. The peak growth hormone (GH) secretion in the experimental session was more than 2.4-fold higher than during the control session (p <.001). The quality of sleep during the experimental session was significantly better than in the control session (p <.01). These results suggest that multi-functional fabric wear is effective in inducing deep sleep, increasing GH, and improving the quality of sleep.

How pain and analgesics disturb sleep

OBJECTIVE

Clinical experiences as well as specific investigations show that pain and sleep disturbances are closely correlated. The aims of this review are first to describe sleep disturbances related to painful medical diseases and analgesics and secondly to propose management possibilities for these sleep disturbances.

METHOD

The viewpoints presented were based mainly on objective rest activity and sleep studies using actigraphy and polysomnography.

RESULTS

Polysomnographic and actigraphic studies have described significant sleep disturbances in patients suffering from different pain disorders. These disturbances are: reduced sleep efficiency and altered sleep architecture characterized by increased wakefulness and stage 1 non-rapid eye movement sleep, associated with diminished slow wave sleep and rapid eye movement sleep. Sleep disturbances may be related to pain and to the analgesic or sedative medications administered.

CONCLUSION

If many factors, including pain, disease process per se, as well as medication, could disturb sleep, sleep disturbances may also adversely affect the natural course of the painful disease. Improving sleep quantity and quality in patients with painful disorders may break this vicious circle and as consequence enhance the patients' overall health and quality of life.

Neuroendocrine control of growth hormone secretion

The secretion of growth hormone (GH) is regulated through a complex neuroendocrine control system, especially by the functional interplay of two hypothalamic hypophysiotropic hormones, GH-releasing hormone (GHRH) and somatostatin (SS), exerting stimulatory and inhibitory influences, respectively, on the somatotrope. The two hypothalamic neurohormones are subject to modulation by a host of neurotransmitters, especially the noradrenergic and cholinergic ones and other hypothalamic neuropeptides, and are the final mediators of metabolic, endocrine, neural, and immune influences for the secretion of GH. Since the identification of the GHRH peptide, recombinant DNA procedures have been used to characterize the corresponding cDNA and to clone GHRH receptor isoforms in rodent and human pituitaries. Parallel to research into the effects of SS and its analogs on endocrine and exocrine secretions, investigations into their mechanism of action have led to the discovery of five separate SS receptor genes encoding a family of G protein-coupled SS receptors, which are widely expressed in the pituitary, brain, and the periphery, and to the synthesis of analogs with subtype specificity. Better understanding of the function of GHRH, SS, and their receptors and, hence, of neural regulation of GH secretion in health and disease has been achieved with the discovery of a new class of fairly specific, orally active, small peptides and their congeners, the GH-releasing peptides, acting on specific, ubiquitous seven-transmembrane domain receptors, whose natural ligands are not yet known.

A reexamination of the relationship between growth hormone secretion and slow wave sleep using delta wave analysis

Sleep onset growth hormone secretion is a reliable and reproducible finding in young adults and children. Secretion typically occurs during the first non-REM period of sleep and, despite some evidence to the contrary, growth hormone secretion has frequently been associated with the first period of slow wave sleep. By measuring delta wave activity (0.5-2 Hz) instead of slow wave sleep and, accounting for the within subject variability, it has not been possible to demonstrate a consistent or statistically significant linear relationship between delta wave activity and sleep-related growth hormone secretion. This suggests the presence of more complex mediating factors and the possibility that sleep onset and growth hormone secretion are two separate processes which are independently stimulated by events associated with sleep onset.

The effect of moderate weight loss on overnight growth hormone and cortisol secretion in healthy female volunteers

The effects of moderate weight loss on overnight growth hormone and cortisol secretion were determined in 11 healthy women volunteers who lost an average of 3.1 kg in weight after undertaking a 1000-kcal diet for 3 weeks. There was a reduction in sleep-related growth hormone secretion and an increase in the value of the nocturnal cortisol nadir although mean overnight cortisol secretion was not significantly altered. Moderate weight loss may contribute towards some of the endocrine abnormalities seen in depressed patients.

Hypothalamic control of GH secretion: pathophysiology and clinical implications

GH is secreted episodically. Its pattern is regulated by the interplay of a releasing and a release-inhibiting hormone of hypothalamic origin. Modulation occurs by metabolic factors (glucose, free fatty acids, ketone bodies, amino acids). Altered GH secretion has been observed in states of metabolic derangement such as diabetes mellitus, malnutrition and obesity. Further modulation occurs by extrahypothalamic CNS structures. In man--but not in animals, including subhuman primates--sleep has an important effect on GH secretion. A defective GH secretory pattern has been found to occur in several states of sleep disturbance, such as sleep deprivation, narcolepsy, severe psychosocial derangement, the apallic syndrome. Other CNS influences on GH secretion are related to stress, emotional changes and psychiatric disturbances. The exact mechanisms by which most of these influences are relayed to the GH secretory apparatus of the hypothalamus remain yet to be investigated.

Trazodone enhances sleep in subjective quality but not in objective duration

Nine volunteer poor sleepers, of mean age 61 years, took trazodone 150 mg nightly for 3 weeks, preceded by 2 weeks and followed by 1 week of matching blanks, in order to examine the effects of electrophysiologically-recorded and subjectively-rated sleep. The second of the initial weeks of matching blanks served as a baseline week. In the subjective ratings, sleep improved in quality on trazodone, significantly so in the first and second weeks of intake, though with significant rebound insomnia on the second withdrawal night. Trazodone halved the frequency of arousals interrupting sleep, and it reduced the time spent in stage 1 (drowsiness). It increased the duration of slow-wave sleep (stages 3 + 4), with a negative rebound following withdrawal. It reduced the time spent in REM sleep, with a rebound above baseline levels after withdrawal. Trazodone did not change total sleep duration, nor the time required to fall asleep. The effects of trazodone were sustained or became enhanced during the period of intake. They persisted for over 24 h after the last dose, and rebound effects were maximal on the second withdrawal night.

Effect of sleep deprivation on dopamine receptor function in normal subjects

Twenty-four hours sleep deprivation significantly decreased the growth hormone response to the dopamine receptor agonist, apomorphine HCl, in five normal men (0.5 mg s.c.) and one woman (0.75 mg s.c.) but had no effect on basal or post-apomorphine prolactin concentrations. These results suggest that sleep deprivation decreases the sensitivity of certain central dopamine receptors. The relevance of this finding to the antidepressant effect of sleep deprivation is unclear.

Growth hormone release during sleep in growth-retarded children with normal response to pharmacological tests

Twenty-one prepubertal children of small stature, 10 boys and 11 girls, aged from 4-3 to 12-8 years, were studied. Their height was less than 3rd centile, and during the preceding year all had a growth rate less than 4-5 cm/year. Arginine and L-dopa tests were given, and the release of growth hormone (GH) during monitored sleep was investigated. On the basis of the electroencephalogram and horizontal electro-oculogram, sleep was divided into stages 1-2-3-4 and rapid-eye-movement. All the children had a GH response greater than 8 ng/ml in at least one of the two pharmacological tests, and were therefore accepted as not suffering from GH deficiency. In all 21 children during sleep there was at least one secretory peak with GH greater than 8 ng/ml. Of a total of 46 secretory peaks recorded, 22 (48%) took place during deep, slow sleep (stages 3-4), 10 (22%) during light sleep (stage 2), 10 (22%) during REM sleep, and 4 (8%) during wakening. In 4 patients (19%) no secretory peak was observed during stages 3-4, even though there were peaks at other times. The data (a) show that it is essential to monitor GH throughout the night to ascertain with certainty the presence or absence of physiological secretory peaks of GH; (b) emphasise the rare disagreement between pharmacological and physiological tests; (c) suggest the use of this physiological test for GH secretion in those cases where the insulin test may be hazardous.

Effects of selective sleep deprivation on sleep-linked prolactin and growth hormone secretion

1. The secretion of prolactin and growth-hormone (hGH) was investigated during sleep in 10 healthy volunteers (8 males and 2 females): The comparison of one baseline night, one night after daytime physical exercise, and one night with selective deprivation of sleep stages 3 and 4 and paradoxical sleep showed clear differences of prolactin and hGH secretion during sleep. 2. Prolactin secretion is entrained into the sleep cycle of Non-REM and REM periods. A maximum of plasma hormone elevations occurs during the first quarter of sleep cycles, i.e., during Non-REM periods and less frequent rises at the end of the cycles, mainly during REM periods. 3. In contrast to growth hormone, concentrations of prolactin remain high also during later cycles occurring toward morning. This shows that high prolactin, but not high concentrations of hGH, regularly occur during sleep cycles with small amounts of slow-wave sleep. 4. Maximal prolactin concentrations during sleep are affected neither by preceding daytime physical exercise nor by selective deprivation of slow sleep stages 3 and 4. This is further evidence that slow-wave sleep stages are not necessary for the development of high plasma prolactin concentrations. However, peak values of growth hormone in the first and second cycle are significantly diminished after selective deprivation of sleep stages 3 and 4. 5. In abnormally long sleep cycles with artificial delay of the first REM period, the cyclical rhythmicity of prolactin release seems disturbed. This is further evidence for the sleep-dependent rhythmicity in the secretion of this hormone.

Mesoridazine and human sleep

1 Mesoridazine, a phenothiazine of short half-life, and potentially useful as an hypnotic, has here been investigated using volunteers of late middle age. 2 The electrophsiological recording of all-night sleep was studied in seven subjects for a 7-week period during which ther received mesoridazine (10 mg nightly) for 3 weeks. The drug reduced the frequency of transitions into wakefulness and stage 1 (drowsiness) and reduced the time spent in stage 1; there was a withdrawal rebound. Mesoridazine increased REM sleep above baseline levels and a rebound fall below baseline occurred on withdrawal. The drug did not alter the amount of stage 3 + 4 slow wave sleep. 3 Subjective self-ratings were assessed in a 6-week study of sixteen subjects. Sleep quality improved on mesoridazine (10 mg nightly) but there was diminution of zest and freshness 20 min after rising. Daytime concentration and anxiety were rated as not affected either by administration or withdrawal.

Isocaloric diet changes and electroencephalographic sleep

Electroencephalographic (E.E.G.) sleep changes were studied in eight young healthy male subjects who were given a normal balanced diet or a high-carbohydrate/low-fat or low-carbohydrate/high-fat isocaloric diet, according to an experimental design. Significantly less slow-wave sleep (S.W.S.) was found after consuming a high-carbohydrate/low-fat diet than after consuming a normal balanced diet or a low-carbohydrate/high-fat diet. The latter two diets did not differ in terms of the amounts of S.W.S. Both high-carbohydrate/low-fat and low-carbohydrate/high-fat isocaloric diets, especially the former, were associated with significantly more rapid-eye-movement (R.E.M.) sleep than was the normal balanced diet. These findings emphasise the importance of daily diet for the following night's sleep.

Two anti-anxiety drugs: a psychoneuroendocrine study

Eight males were studied during 27 weeks, including two periods of five weeks during which they received clinical doses of sodium amylobarbitone and benzoctamine. Substitution of placebo for either drug caused raised anxiety and impairment of mental concentration. The drugs reduced restlessness during sleep and reduced paradoxical sleep. By the fifth week of sodium amylobarbitone, although sleep was still less restless in the early night it was more restless than normal in the late night.Blood samples were taken half-hourly during sleep by indwelling venous catheter. Plasma growth hormone concentration was little affected during drug administration but rose temporarily after withdrawal. There was a reduction of plasma corticosteroid concentration during sleep throughout administration of the drugs and a rebound above normal during the first withdrawal week.

Sleep and growth hormone

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Chronic fenfluramine administration: some cerebral effects

Human cerebral function was monitored electrophysiologically during sleep over a period of months before, during, and after the intake of fenfluramine, 40-120 mg/day. Effects included dose-related reduction of paradoxical sleep, increase of intra-sleep restlessness, and changes in E.E.G. slow-wave sleep. It is hypothesized that weight loss may be associated with increase of the last. Grinding of teeth (bruxism) also was noted.Long-term studies make it possible to demonstrate changing central effects with time, including tolerance phenomena. Withdrawal abnormalities are related to the time taken for the drug to be eliminated-in the present case reaching a maximum four days after withdrawal.