The Growth Hormone Secretory Pattern and Statural Growth

Robinson, Iain C. A. F.; Hindmarsh, Peter C.

doi:10.1002/cphy.cp070512

Cited by 14 publications

(7 citation statements)

References 838 publications

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“…However, plasma ghrelin and GH levels are not strictly correlated, and cross-ApEn did not reveal a great synchronism between these two parameters. This result might have been expected because, based on hypophyseal portal rat blood sampling data, GHRH and SRIF fluctuations are also involved in this phenomenon (25,26), with SRIF withdrawal being a prerequisite for GHRH action (50). It remains to be demonstrated directly, on rat portal blood measurements, whether ghrelin does inhibit SRIF release as already observed in vitro (12).…”

Section: Discussionmentioning

confidence: 64%

“…As recently reviewed, the dual action on GH secretion and food intake as well as the dual localization of ghrelin and its receptors in hypothalamus and stomach immediately raise the question of the interdependency of these actions (24). Many studies have linked nutrition and episodic GH secretion although these relationships vary from species to species, undernutrition reducing GH pulsatility in the rat, while the converse is true in humans (25). One common property of feeding behavior and GH secretion is their rhythmicity.…”

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confidence: 99%

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Ultradian Rhythmicity of Ghrelin Secretion in Relation with GH, Feeding Behavior, and Sleep-Wake Patterns in Rats

Tolle¹,

Bassant²,

Zizzari³

et al. 2002

Endocrinology

222

114

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Ghrelin, an endogenous ligand for the GHS receptor, stimulates GH secretion and gastrointestinal motility and has orexigenic effects. In this study, the relationships between ghrelin, GH secretion, feeding behavior, and sleep-wake patterns were investigated in adult male rats. The half-life of exogenous ghrelin (10 microg i.v.) in plasma was about 30 min. Repeated administration of ghrelin at 3- to 4-h intervals (one during lights-on and two during lights-off periods) increased GH release and feeding activity, and decreased rapid eye movement sleep duration. Endogenous plasma ghrelin levels exhibited pulsatile variations that were smaller and less regular compared with those of GH. No significant correlation between GH and ghrelin circulating levels was found, although mean interpeak intervals and pulse frequencies were close for the two hormones. In contrast, ghrelin pulse variations were correlated with food intake episodes in the lights off period, and plasma ghrelin concentrations decreased by 26% in the 20 min following the end of the food intake periods. A positive correlation between ghrelin levels and active wake was found during the first 3 h of the dark period only. In conclusion, ghrelin, in addition to affecting GH secretion, gastrointestinal motility, and feeding activity, also modifies sleep-wake patterns. However, a direct action of ghrelin per se or the indirect effects of feeding (and all of its attendant metabolic sequelae) on sleep cannot be differentiated. Moreover, ghrelin secretion is pulsatile and directly related to feeding behavior only.

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Section: Discussionmentioning

confidence: 64%

mentioning

confidence: 99%

Ultradian Rhythmicity of Ghrelin Secretion in Relation with GH, Feeding Behavior, and Sleep-Wake Patterns in Rats

Tolle¹,

Bassant²,

Zizzari³

et al. 2002

Endocrinology

222

114

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“…sex hormones | body growth | calcium signaling | systems biology I n most species, males and females display a marked phenotypic divergence in body size, with increased growth rate and body mass being a predominantly masculine trait. Furthermore, in all species examined to date, the growth hormone (GH) axis demonstrates sex-specific differences in hormone contents, secretory outputs, and secretory patterns (1) and their effects on gene expression (2)(3)(4). The secretion of GH is controlled by hypothalamic GH-releasing hormone (GHRH) and somatostatin, and there is good evidence for sex-specific imprinting on hypothalamic hypophysiotropic neurons exerted by gonadal steroid exposure early in life (5), with ongoing effects during puberty (6).…”

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confidence: 99%

Pituitary growth hormone network responses are sexually dimorphic and regulated by gonadal steroids in adulthood

Sánchez-Cárdenas

Fontanaud

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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There are well-recognized sex differences in many pituitary endocrine axes, usually thought to be generated by gonadal steroid imprinting of the neuroendocrine hypothalamus. However, the recognition that growth hormone (GH) cells are arranged in functionally organized networks raises the possibility that the responses of the network are different in males and females. We studied this by directly monitoring the calcium responses to an identical GH-releasing hormone (GHRH) stimulus in populations of individual GH cells in slices taken from male and female murine GH-eGFP pituitary glands. We found that the GH cell network responses are sexually dimorphic, with a higher proportion of responding cells in males than in females, correlated with greater GH release from male slices. Repetitive waves of calcium spiking activity were triggered by GHRH in some males, but were never observed in females. This was not due to a permanent difference in the network architecture between male and female mice; rather, the sex difference in the proportions of GH cells responding to GHRH were switched by postpubertal gonadectomy and reversed with hormone replacements, suggesting that the network responses are dynamically regulated in adulthood by gonadal steroids. Thus, the pituitary gland contributes to the sexually dimorphic patterns of GH secretion that play an important role in differences in growth and metabolism between the sexes. sex hormones | body growth | calcium signaling | systems biology I n most species, males and females display a marked phenotypic divergence in body size, with increased growth rate and body mass being a predominantly masculine trait. Furthermore, in all species examined to date, the growth hormone (GH) axis demonstrates sex-specific differences in hormone contents, secretory outputs, and secretory patterns (1) and their effects on gene expression (2-4). The secretion of GH is controlled by hypothalamic GH-releasing hormone (GHRH) and somatostatin, and there is good evidence for sex-specific imprinting on hypothalamic hypophysiotropic neurons exerted by gonadal steroid exposure early in life (5), with ongoing effects during puberty (6). This has led to the conclusion that the sexually dimorphic control of GH patterns reflects sex differences in GHRH and somatostatin inputs to the pituitary gland. Acute changes in gonadal steroid environment drastically alter the patterns of GH pulsatility in adulthood (7,8); however, although they receive sexually dimorphic inputs (9, 10), GHRH neurons do not display sex-specific electrical characteristics (9, 11). We have previously shown that GH cells in the male mouse pituitary gland form an extensive homotypic cell network with an architecture that exhibits marked plasticity during sexual maturation and that can be altered by gonadectomy (12). Thus, it was important to determine whether male and female pituitary glands would show different responses to the same stimulus in the absence of any hypothalamic influence. To explore this, we assessed the functional activit...

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“…Hypothalamic growth hormone-releasing hormone (GHRH) neurons control the pulsatile secretion of growth hormone (GH) from the pituitary gland 1 , thereby regulating growth and metabolism. In addition, these neurons are involved in the central regulation of glucose homeostasis 2 .…”

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confidence: 99%

“…Hence, GHRH neurons of may in fact be capable of displaying patterned/rhythmic electrical discharges, and this may stem from differential responsiveness to their afferent SST-, GABA- and glutamate inputs. The identification of the mechanisms underlying GHRH neuron activity are important, since defects in pulsatile GH release are associated with disorders of growth and impaired responses to hypoglycemia during diabetes 1 11 .…”

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confidence: 99%

Somatostatin triggers rhythmic electrical firing in hypothalamic GHRH neurons

Osterstock

Mitutsova

Barre

et al. 2016

Sci Rep

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Hypothalamic growth hormone-releasing hormone (GHRH) neurons orchestrate body growth/maturation and have been implicated in feeding responses and ageing. However, the electrical patterns that dictate GHRH neuron functions have remained elusive. Since the inhibitory neuropeptide somatostatin (SST) is considered to be a primary oscillator of the GH axis, we examined its acute effects on GHRH neurons in brain slices from male and female GHRH-GFP mice. At the cellular level, SST irregularly suppressed GHRH neuron electrical activity, leading to slow oscillations at the population level. This resulted from an initial inhibitory action at the GHRH neuron level via K+ channel activation, followed by a delayed, sst1/sst2 receptor-dependent unbalancing of glutamatergic and GABAergic synaptic inputs. The oscillation patterns induced by SST were sexually dimorphic, and could be explained by differential actions of SST on both GABAergic and glutamatergic currents. Thus, a tripartite neuronal circuit involving a fast hyperpolarization and a dual regulation of synaptic inputs appeared sufficient in pacing the activity of the GHRH neuronal population. These “feed-forward loops” may represent basic building blocks involved in the regulation of GHRH release and its downstream sexual specific functions.

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The Growth Hormone Secretory Pattern and Statural Growth

Cited by 14 publications

References 838 publications

Ultradian Rhythmicity of Ghrelin Secretion in Relation with GH, Feeding Behavior, and Sleep-Wake Patterns in Rats

Ultradian Rhythmicity of Ghrelin Secretion in Relation with GH, Feeding Behavior, and Sleep-Wake Patterns in Rats

Pituitary growth hormone network responses are sexually dimorphic and regulated by gonadal steroids in adulthood

Somatostatin triggers rhythmic electrical firing in hypothalamic GHRH neurons

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