Growth hormone secretion during sleep in male depressed patients

Association of growth hormone deficiency (GHD) with anxiety and depression: experimental data and evidence from GHD children and adolescents

Anxiety and depression are among the commonest emotional problems in children and young adolescents. They are encountered with even higher prevalence in children and adults with growth hormone deficiency (GHD). Alterations in the somatotropic axis, as observed in both GH/IGF1 deficiency and excess, can produce permanent changes in brain tissue structure. The growth hormone/insulin-like growth factor 1 (GH/IGF1) axis seems to exert a regulatory effect on brain function and neurogenesis, especially in the hippocampus, a brain region associated with mental and emotional disorders, such as depression and anxiety. There is evidence from animal models of the possible interrelationship of the endocrine system with the pathogenesis of emotional disorders. Moreover, clinical data support the association of GHD and mood disorders, which are often reversed by GH replacement therapy. However, the causal relationship and the mechanism underlying this association are to date obscure and remain to be clarified. The present review reports experimental data from animal models regarding the role of GH/IGF1 in emotional disorders and focuses on clinical data on the presence of these disorders in children with GHD and their response to GH therapy.

Gut Hormones as Potential Therapeutic Targets or Biomarkers of Response in Depression: The Case of Motilin

Recent research has identified the gut–brain axis as a key mechanistic pathway and potential therapeutic target in depression. In this paper, the potential role of gut hormones as potential treatments or predictors of response in depression is examined, with specific reference to the peptide hormone motilin. This possibility is explored through two methods: (1) a conceptual review of the possible links between motilin and depression, including evidence from animal and human research as well as clinical trials, based on a literature search of three scientific databases, and (2) an analysis of the relationship between a functional polymorphism (rs2281820) of the motilin (MLN) gene and cross-national variations in the prevalence of depression based on allele frequency data after correction for potential confounders. It was observed that (1) there are several plausible mechanisms, including interactions with diet, monoamine, and neuroendocrine pathways, to suggest that motilin may be relevant to the pathophysiology and treatment of depression, and (2) there was a significant correlation between rs2281820 allele frequencies and the prevalence of depression after correcting for multiple confounding factors. These results suggest that further evaluation of the utility of motilin and related gut peptides as markers of antidepressant response is required and that these molecular pathways represent potential future mechanisms for antidepressant drug development.

A Systematic Review of Growth Hormone in Pain Medicine: From Rodents to Humans

Objective

Growth hormone (GH) and GH-related signaling molecules play an important role in nociception and development of chronic pain. This review aims to examine the potential molecular mechanisms through which GH-related signaling modulates sensory hypersensitivity in rodents, the clinical pharmacology of GH, and the clinical evidence of GH treatment for several common pain syndromes.

Methods

A search was conducted using the PUBMED/MEDLINE database, Scopus, and the Cochrane library for all reports published in English on GH in pain management from inception through May 2018. A critical review was performed on the mechanisms of GH-related signaling and the pharmacology of GH. The levels of clinical evidence and implications for recommendations of all of the included studies were graded.

Results

The search yielded 379 articles, of which 201 articles were deemed irrelevant by reading the titles. There were 53 reports deemed relevant after reading abstracts. All of these 53 articles were retrieved for the analysis and discussion.

Conclusions

Dysfunction of the GH/insulin-like growth factor 1 (IGF-1)/ghrelin axis was linked to hyperalgesia and several common clinical pain syndromes. Low levels of GH and IGF-1 were linked to pain hypersensitivity, whereas ghrelin appeared to provide analgesic effects. Pretreatment of GH reversed mechanical and thermal hypersensitivity in an animal model of inflammatory pain. Clinical trials support GH treatment in a subgroup of patients with fibromyalgia syndrome (level of evidence: 1B+) or chronic lower back pain syndrome (level of evidence: 2C+).

The behavioural profile of gamma-hydroxybutyrate, gamma-butyrolactone and 1,4-butanediol in humans

Gamma-hydroxybutyrate (GHB) is a putative neurotransmitter, a drug of abuse, and a medical treatment for narcolepsy and other neuropsychiatric disorders. Its precursors gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD) are endogenously converted to GHB and thereby exert their psychobehavioural effects. In humans, GHB has a wide spectrum of properties ranging from stimulation and euphoria in lower doses, to sedation, deep sleep, and coma after ingestion of high doses. However, behavioural studies in healthy volunteers remain scarce and are usually limited to psychomotor performance testing. Most available data arise from either qualitative studies with illicit users or clinical trials examining therapeutic properties of GHB (then usually termed sodium oxybate). Here, we present an overview of the behavioural effects of GHB, GBL, and 1,4-BD in these three populations. GHB and its precursors strongly influence behaviours related to core human autonomic functions such as control of food intake, sexual behaviour, and sleep-wake regulation. These effects are instrumentalised by illicit users and clinically utilised in neuropsychiatric disorders such as narcolepsy, fibromyalgia, and binge-eating syndrome. Considering the industry withdrawal from psychopharmacology development, repurposing of drugs according to their behavioural and clinical profiles has gained increasing relevance. As such, GHB seems to be an attractive candidate as an experimental therapeutic in depression.

Growth hormone measurements in the diagnosis and monitoring of acromegaly

Before the availability of immunoassays for IGF-I, growth hormone (GH) measurement was the sole method used in the biochemical assessment of acromegaly. IGF-I has since been established as the most reliable biochemical indicator of acromegaly. The last 25 years has seen important advances in the understanding of the neuroregulation and in the characterization of GH secretion in acromegaly. The availability of supersensitive GH has changed many aspects of the interpretation of GH-value in the management of acromegaly. Hypersecretion and abnormal neuroregulation characterize GH secretion in acromegaly. GH can be measured in many ways: as a single random sample, as multiple samples, either spontaneously or as an integral part of a dynamic test. These approaches give useful information on diagnosis, therapy, and prognosis. There is a place for measuring GH in the management of acromegaly although it complements that of IGF-I.

Neurobiology of depression in children and adolescents

This article reviews classical and updated studies of the neurobiology of depressive disorders in children and adolescents. Most studies of childhood and adolescent depression and suicide have followed up the observations and methods used in studies in adults. These studies include neuroendocrine studies, which particularly look at the hypothalamic-pituitary-adrenal axis, the serotonergic system, peripheral blood and cerebrospinal fluid biologic markers, genetics, gene-environment interactions and sleep studies, and neuroimaging and postmortem studies, although in these areas the number of studies is limited.

10-year research update review: the epidemiology of child and adolescent psychiatric disorders: II. Developmental epidemiology

OBJECTIVE

To describe the growth of developmental epidemiology in the past decade and to illustrate it with examples of recent studies.

METHOD

A review of publications on developmental epidemiology in the past 10 years and a discussion of some key examples.

RESULTS

The authors describe how the interaction between developmental psychopathology and psychiatric epidemiology has produced developmental epidemiology, the study of patterns of distribution of psychiatric disorders in time as well as in space. They give two examples of the kinds of questions that developmental epidemiology can help to answer: (1) Is the prevalence of autism increasing? Does the use of vaccines explain the increase? (2) Is there an epidemic of child and adolescent depression? Finally, they describe two areas of science that are beginning to inform developmental epidemiology: molecular genetics and the use of biological measures of stress.

CONCLUSIONS

While child and adolescent psychiatric epidemiology continues, as described in the first of these reviews, to address questions of prevalence and burden, it has also expanded into new areas of research in the past decade. In the next decade, longitudinal epidemiological data sets with their rich descriptive data on psychopathology and environmental risk over time and the potential to add biological measures will provide valuable resources for research into gene-environment correlations and interactions.

Endocrine disturbances in depression

Depression is one of the most common psychiatric disorders. For a long time, clinicians suspected a causal link between depression and the endocrine system. The most frequently occurring endocrine abnormality in depressed subjects is hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis. CRH and AVP are likely to play a substantial role in the pathophysiology of this disorder, and their receptors appear to be a specific target for future antidepressant drugs. Depression also affects the hypothalamic-pituitary-GH (HPGH) and -thyroid (HPT) axes. Alterations in the reproductive system may also play a role in the pathology of depression. In addition, there is increasing evidence that leptin and neurosteroids, such as DHEA, are implicated in mood disorders.

Twenty-four hour growth hormone secretion in patients with panic disorder

BACKGROUND

Patients with panic disorder have blunted growth hormone (GH) responses to clonidine, suggesting subsensitivity of post-synaptic alpha(2)-adrenoreceptors, presumably in response to excessive central noradrenergic outflow. However, basal levels of GH release over a full circadian cycle have not been examined in panic. Reduced basal GH release would suggest an overall hypo-active GH system rather than a specific alpha-adrenergic abnormality.

METHODS

To determine whether panic patients show reduced basal GH secretion, 20 patients and 12 healthy controls were studied. Blood samples were drawn every 15 min for 24 h and plasma was assayed for GH. Patients were restudied during successful treatment with alprazolam. Groups were compared on overnight and daytime GH secretion and circadian patterns of release.

RESULTS

Patients showed normal levels on all measures of GH release. Treatment may have reduced nocturnal GH release slightly, but treated patients still did not differ from controls. The normal predominance of sleep over waking GH secretion was seen in both groups.

CONCLUSIONS

Panic patients, in contrast to depressed patients, have normal somatotrophic axis activity when measured in a resting state over a full circadian cycle. GH dysregulation may only be evident in these patients in activation paradigms and has been most consistently demonstrated by challenges with the alpha(2)-noradrenergic agonist, clonidine.

24-h Monitoring of plasma norepinephrine, MHPG, cortisol, growth hormone and prolactin in depression

Depression is associated with alterations in hormone and catecholamine circadian rhythms. Analysis of these alterations has the potential to distinguish between three neurobiological models of depression, the catecholamine model, the phase advance model and the dysregulation model. Although a number of studies of 24-h rhythms have been reported, inconsistencies among the findings have complicated efforts to model the chronobiology of depression. The present study takes advantage of frequent plasma sampling over the 24-h period and a multioscillator cosinor model to fit the 24-h rhythms.

METHOD

Plasma levels of norepinephrine, cortisol, prolacatin and growth hormone were sampled at 30-min intervals, and MHPG at 60-min intervals, over a 24-h period in 22 patients with major depressive disorder and 20 healthy control volunteers.

RESULTS

The depressed patients had phase advanced circadian rhythms for cortisol, norepinephrine and MHPG, phase advanced hemicircadian rhythms for cortisol and prolactin, and a phase advanced ultradian rhythm for prolactin compared to healthy control subjects. In addition, the rhythm-corrected 24-h mean value (mesor) of norepinephrine was lower in the depressed patients compared to the healthy controls. There also was a poorer goodness-of-fit for norepinephrine to the circadian oscillator in the depressed patients relative to the healthy controls.

CONCLUSIONS

These findings provide partial support for the dysregulation model of depression and are consistent with those studies that have found phase advances in cortisol, norepinephrine and MHPG rhythms in depression.

Sleep and endocrinology

A bidirectional interaction between sleep electroencephalogram and endocrine activity is well established in various species including humans. Various hormones (peptides and steroids) participate in sleep regulation. A key role was shown for the reciprocal interaction between sleep-promoting growth hormone-releasing hormone (GHRH) and sleep-impairing corticotropin-releasing hormone (CRH). Changes in the GHRH : CRH ratio result in changes of sleep-endocrine activity. It is thought that the change of this ratio in favour of CRH contributes to aberrations of sleep during ageing and depression (shallow sleep, blunted GH and elevated cortisol). Besides GHRH, ghrelin and galanin enhance slow wave sleep. Somatostatin is another sleep-impairing factor. Neuropeptide Y acts as a CRH antagonist and induces sleep onset. There are hints that CRH promotes rapid eye movement sleep (REMS). In animals prolactin enhances REMS. In humans vasoactive intestinal polypeptide (VIP) appears to play a role in the temporal organization of sleep as, after VIP, the non-REMS-REMS cycle decelerated. Cortisol appears to enhance REMS. Finally, gonadal hormones participate in sleep regulation. Oestrogen replacement therapy and CRH-1 receptor antagonism in depression are beneficial clinical applications of sleep-endocrine research.

Birth weight and the risk of depressive disorder in late life

BACKGROUND

Low birth weight is a risk factor for coronary heart disease, diabetes, stroke and hypertension. Depression is highly associated with these conditions.

AIMS

To examine the association between birth weight and depression in late life.

METHOD

A total of 882 singleton term births in the 1920s had contemporary records of birth weight and weight at 1 year. At 68 years all completed the Geriatric Depression Scale and 867 completed the Geriatric Mental State Examination. A logistic regression was used to analyse the associations between depression, birth weight and weight at 1 year while adjusting for known risk factors.

RESULTS

Current social class, social class at birth, recent bereavement, social isolation and physical illness increased the risk of depression. After adjusting for these and weight at 1 year, the odds ratios for depression among men, but not women, rose incrementally with decreasing birth weight (1.0, 12.8; for continuous variable, P<0.007).

CONCLUSIONS

Foetal undernutrition predisposes men to depression in late adult life. If replicated, these results would suggest a neurodevelopmental aetiology of depression, possibly mediated by programming of the hypothalamic-pituitary-adrenal axis.

Insulin-like growth factor 1 and growth hormone binding protein in depression: a preliminary communication

This study was undertaken in order to advance our understanding of the distal growth hormone axis in depression. Insulin-like growth factor 1 (IGF-1) and growth hormone binding protein (GHBP) were measured in a group of 19 depressed women and a group of 16 healthy women. Using a generalized linear model, IGF-1 levels were negatively correlated with age (p = 0.0001), influenced by menstrual phase (p = 0.016), and significantly increased in the depressed group (p = 0.02). Using the same type of analysis, GHBP was significantly related to menstrual phase (p = 0.0001) and body mass index (p = 0.0001), but was not significantly different in patients and controls. IGF-1 and GHBP were positively correlated among healthy subjects (r = 0.46, p = 0.08), but not among depressed patients (r = -0.16, p = 0.51), although these correlation coefficients were not statistically significantly different from each other. These findings confirm the importance of several physiological factors in the regulation of IGF-1 and GHBP, and suggest that depression further influences this regulation.