Phoenixin and Its Role in Reproductive Hormone Release

2019 ◽  
Vol 37 (04) ◽  
pp. 191-196 ◽  
Author(s):  
Sophie A. Clarke ◽  
Waljit S. Dhillo
Keyword(s):  
Animal Species ◽  
Hormone Secretion ◽  
Physiological Role ◽  
Peptide Sequence ◽  
Reproductive Hormone ◽  
Dependent Manner ◽  
Hormone Release ◽  
Gastrointestinal Tissue ◽  
Gonadotrophin Releasing Hormone

AbstractPhoenixin is novel neuropeptide, recently identified following the description of a peptide sequence highly conserved across several animal species, including humans, cows, and pigs. Expressed both centrally in the hypothalamus and arcuate nucleus and peripherally in cardiac and gastrointestinal tissue, it appears to modulate reproductive hormone secretion in a gonadotrophin-releasing hormone–dependent manner and may also influence anxiety and memory. While there remains much to be described regarding its signaling, this review assesses the currently available literature in both animal and human studies to summarize our understanding of the physiological role of this novel neuropeptide, and its function in reproductive hormone release.

scholarly journals History and perspectives of pituitary folliculo-stellate cell research

2005 ◽  
Vol 153 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Wilfried Allaerts ◽  
Hugo Vankelecom
Keyword(s):  
Cell Population ◽  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Physiological Role ◽  
Pituitary Cell ◽  
Stem Cell Population ◽  
Cell Group ◽  
Pituitary Hormone ◽  
Topographical Distribution

Historically, the study of folliculo-stellate (FS) cells of the anterior pituitary dates back to the onset of electron microscopical observation of the pituitary gland. The morphological and electrophysiological characteristics, topographical distribution and contribution to intercellular junctions of these FS cells have been instrumental to the understanding of their putative function. Moreover, many studies have documented the role of FS cells as a source of newly discovered peptides, growth factors and cytokines. Quantitative immunohistochemical observation of FS cells in situ and functional in vitro studies, using either cultured FS cells or cells from an immortalized FS cell line, forwarded the notion of immunophenotypical and functional heterogeneity of the FS cell group. Double immunolabeling with a classical FS cell marker (S-100 protein) and with major histocompatibility complex class II markers characteristic for dendritic cells (DC) have shown a considerable overlap of FS cells with DC. The latter cells are immunocompetent cells belonging to the mononuclear phagocyte system. In this review, the FS cell heterogeneity is discussed with respect to the question of their embryological origin and developmental fate and with respect to the physiological relevance of functionally heterogeneous subpopulations. Recent findings of a myeloid origin of part of the interstitial cells of the anterior pituitary are confronted by other developmental paradigms of pituitary cell differentiation. The possibility that FS cells represent an adult stem cell population of the pituitary is critically examined. Also the physiological role of FS cells in the interferon-γ- and nitric oxide-mediated effects on pituitary hormone secretion is discussed. New approaches for the study of this enigmatic cell group using immortalized cell lines and new markers for an hitherto unrecognized pituitary cell population, the so-called ‘side population’, are evaluated.

Somatostatin Inhibits prolactin secretion in the estradiol primed male rat

1981 ◽  
Vol 59 (10) ◽  
pp. 1082-1088 ◽  
Author(s):  
G. R. Cooper ◽  
S. H. Shin
Keyword(s):  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Blocking Agent ◽  
Prolactin Secretion ◽  
Male Rats ◽  
Male Rat ◽  
Dependent Manner ◽  
Intact Male ◽  
Plasma Prl

Somatostatin inhibits not only growth hormone secretion, but also the secretion of several other hormones. The role of somatostatin in prolactin (PRL) secretion has not been clearly demonstrated. The present study was undertaken to examine the effects of somatostatin on rat PRL secretion in several different circumstances where the circulating PRL level is elevated: (1) the estradiol primed intact male rat, (2) normal and (3) estradiol primed rats pretreated with pimozide, (4) normal and (5) estradiol primed hypophysectomized male rats with adenohypophyses grafted under the kidney capsule (HAG rat). Blood samples (70 μL) were taken every 2 min via an indwelling atrial cannula from conscious, unrestrained animals. In the estradiol primed intact rats, a bolus injection of somatostatin (10, 100, and 1000 μg/kg) lowered PRL levels in a dose-dependent manner. When the PRL concentration was elevated by the administration of pimozide (3 mg/kg), a dopaminergic receptor blocking agent, somatostatin was ineffective in decreasing plasma PRL concentration but the PRL concentration was lowered by somatostatin when the rat had been primed with estradiol. Somatostatin had no effect on the normal HAG rats, but lowered the plasma PRL concentration in the estradiol primed HAG rats. Since somatostatin inhibits PRL secretion only in the estradiol primed rats, it is suggested that estradiol priming creates a new environment, presumably via new or altered receptors, which can be inhibited by somatostatin.

Effect of actively immunizing sheep against growth hormone-releasing hormone or somatostatin on spontaneous pulsatile and neostigmine-induced growth hormone secretion

1995 ◽  
Vol 144 (1) ◽  
pp. 83-90 ◽  
Author(s):  
E Magnan ◽  
L Mazzocchi ◽  
M Cataldi ◽  
V Guillaume ◽  
A Dutour ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Body Weight ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Physiological Role ◽  
Gh Secretion ◽  
Igf I ◽  
Plasma Gh ◽  
Hypophysial Portal

Abstract The physiological role of endogenous circulating GHreleasing hormone (GHRH) and somatostatin (SRIH) on spontaneous pulsatile and neostigmine-induced secretion of GH was investigated in adult rams actively immunized against each neuropeptide. All animals developed antibodies at concentrations sufficient for immunoneutralization of GHRH and SRIH levels in hypophysial portal blood. In the anti GHRH group, plasma GH levels were very low; the amplitude of GH pulses was strikingly reduced, although their number was unchanged. No stimulation of GH release was observed after neostigmine administration. The reduction of GH secretion was associated with a decreased body weight and a significant reduction in plasma IGF-I concentration. In the antiSRIH group, no changes in basal and pulsatile GH secretion or the GH response to neostigmine were observed as compared to controls. Body weight was not significantly altered and plasma IGF-I levels were reduced in these animals. These results suggest that in sheep, circulating SRIH (in the systemic and hypophysial portal vasculature) does not play a significant role in pulsatile and neostigmine-induced secretion of GH. The mechanisms of its influence on body weight and production of IGF-I remain to be determined. Journal of Endocrinology (1995) 144, 83–90

scholarly journals Antagonism by Taurine of Morphine Induced Growth Hormone Secretion

1978 ◽  
Vol 5 (1) ◽  
pp. 139-142 ◽  
Author(s):  
R. Collu ◽  
G. Charpenet ◽  
M. J. Clermont
Keyword(s):  
Growth Hormone ◽  
Amino Acid ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Physiological Role ◽  
Pituitary Hormone ◽  
Hormone Release ◽  
Morphine Administration ◽  
Plasma Gh

SUMMARY:The intraperitoneal (IP) or intraventricular (IVT) administration of small amounts of taurine did not modify pentobarbital-induced sleep or pituitary hormone release. However, the drastic increment in plasma GH values induced by morphine administration was completely blocked by the IVT injection of the amino acid. Whether taurine plays a physiological role in the control ofGH secretion is highly speculative.

scholarly journals Emerging Roles of Kisspeptin in Sexual and Emotional Brain Processing

2017 ◽  
Vol 106 (2) ◽  
pp. 195-202 ◽  
Author(s):  
Alexander N. Comninos ◽  
Waljit S. Dhillo
Keyword(s):  
Sexual Arousal ◽  
Hormone Secretion ◽  
Population Level ◽  
Reproductive Hormone ◽  
Hpg Axis ◽  
Brain Processing ◽  
Social Behaviours

The emergence of kisspeptin as a crucial regulator of the hypothalamo-pituitary-gonadal (HPG) axis over the last 14 years has answered many questions as to the control of reproductive hormone secretion from the hypothalamus. More recently, the role of kisspeptin outside the HPG axis has received increasing attention in the hope of delineating the pathways linking various sensory and social behaviours to reproduction. These studies, in a range of species from zebrafish to humans, have identified a role for kisspeptin in behavioural networks related to reproduction including olfaction, audition, fear, anxiety, mood, and sexual arousal. The available evidence suggests that extrahypothalamic kisspeptin signalling encourages positive aspects of emotional and sexual brain processing in a presumed drive towards reproduction and ultimately maintenance of the species at a population level. In this review, we examine these studies, which collectively propose that kisspeptin may integrate sexual and emotional brain processing with the control of the HPG axis.

scholarly journals The role of nutrient sensing in the metabolic changes after gastric bypass surgery

2017 ◽  
Vol 232 (3) ◽  
pp. 363-376 ◽  
Author(s):  
Sandra Steensels ◽  
Matthias Lannoo ◽  
Bert Avau ◽  
Jorien Laermans ◽  
Laurien Vancleef ◽  
...  
Keyword(s):  
Gastric Bypass ◽  
Body Weight ◽  
Glucose Homeostasis ◽  
Glucose Transporter ◽  
Nutrient Sensing ◽  
Dependent Manner ◽  
Hormone Release ◽  
L Cell ◽  
Gut Hormone

Taste receptors coupled to the gustatory G-protein, gustducin, on enteroendocrine cells sense nutrients to regulate gut hormone release. During Roux-en-Y gastric bypass (RYGB) surgery, the altered nutrient flow to more distal regions can affect gustducin-mediated gut hormone release and hence energy and glucose homeostasis. We studied the role of gustducin-mediated signaling in the metabolic improvements and intestinal adaptations along the gut after RYGB surgery in wild-type (WT) and α-gustducin−/− (α-gust−/−) mice. RYGB surgery decreased body weight in WT and α-gust−/− mice, whereas food intake was only decreased in WT mice. Pair-feeding to the RYGB group improved glucose homeostasis to a similar extent in WT mice. GLP1 levels were increased in both genotypes, PYY levels in α-gust−/− mice and octanoyl ghrelin levels were not affected after RYGB surgery. In WT mice, nutrients act via α-gustducin to increase L-cell differentiation (foregut) and L-cell number (foregut and hindgut) in a region-dependent manner. In α-gust−/− mice, the effect on gut hormone levels is probably tuned via increased peptide sensor and glucose transporter expression in the Roux limb and increased caecal butyrate and propionate levels in the hindgut that activate free fatty acid receptors. Finally, signaling via α-gustducin plays a role in the increased ion transport of the foregut but not in the improvement in colonic barrier function. In conclusion, RYGB surgery decreased body weight in both WT and α-gust−/− mice. Elevated plasma GLP1 and PYY levels might mediate this effect, although α-gustducin differentially affects several regulatory systems in the foregut and hindgut, tuning gut hormone release.

scholarly journals Inhibin at 90: From Discovery to Clinical Application, a Historical Review

2014 ◽  
Vol 35 (5) ◽  
pp. 747-794 ◽  
Author(s):  
Yogeshwar Makanji ◽  
Jie Zhu ◽  
Rama Mishra ◽  
Chris Holmquist ◽  
Winifred P. S. Wong ◽  
...  
Keyword(s):  
Hormone Secretion ◽  
Physiological Role ◽  
Historical Review ◽  
Reproductive Function ◽  
Reproductive Hormones ◽  
Pituitary Hormone ◽  
Pituitary Cells ◽  
Organ Systems ◽  
Hypophysiotropic Hormone

When it was initially discovered in 1923, inhibin was characterized as a hypophysiotropic hormone that acts on pituitary cells to regulate pituitary hormone secretion. Ninety years later, what we know about inhibin stretches far beyond its well-established capacity to inhibit activin signaling and suppress pituitary FSH production. Inhibin is one of the major reproductive hormones involved in the regulation of folliculogenesis and steroidogenesis. Although the physiological role of inhibin as an activin antagonist in other organ systems is not as well defined as it is in the pituitary-gonadal axis, inhibin also modulates biological processes in other organs through paracrine, autocrine, and/or endocrine mechanisms. Inhibin and components of its signaling pathway are expressed in many organs. Diagnostically, inhibin is used for prenatal screening of Down syndrome as part of the quadruple test and as a biochemical marker in the assessment of ovarian reserve. In this review, we provide a comprehensive summary of our current understanding of the biological role of inhibin, its relationship with activin, its signaling mechanisms, and its potential value as a diagnostic marker for reproductive function and pregnancy-associated conditions.

ROLE OF THE HETEROGENEITY OF THYROGLOBULIN IN THE SECRETION OF THYROID HORMONE IN MICE

1980 ◽  
Vol 86 (3) ◽  
pp. 413-418 ◽  
Author(s):  
N. BAGCHI ◽  
T. R. BROWN ◽  
B. SHIVERS ◽  
R. E. MACK
Keyword(s):  
Drinking Water ◽  
Chromatographic Analysis ◽  
Hormone Secretion ◽  
Hormone Release ◽  
Basal Rate ◽  
Thyroid Glands ◽  
Hydrolysis Of ◽  
Mouse Thyroid

The rates of thyroglobulin hydrolysis and iodothyronine release from mouse thyroid glands were studied in vitro. Recently iodinated thyroglobulin ('new pool') had been labelled during life by injection of 131I 3 h before removal of the thyroid, 'old pool' thyroglobulin had been labelled by the administration of 125I in the drinking water for 1 week starting 3 weeks earlier. Chromatographic analysis of pronase digests of the thyroid glands showed that the iodothyronine content of the old and new pools were 19·5 and 7·4 per cent respectively. In the basal state the rate of thyroglobulin hydrolysis was lower from the old pool but the rate of hormone secretion was similar from both pools. Thyrotrophin (TSH) increased the rate of thyroglobulin hydrolysis and hormone release from both pools by up to four to six times the basal rate, the effect being maximal 2 h after administration of TSH and lasting for 6–8 h. The rate of thyroglobulin hydrolysis after TSH was similar in both pools but the rate of release of labelled iodothyronines was significantly higher from the old pool. These studies have indicated that although hydrolysis of thyroglobulin proceeds faster in the new pool than in the old ('last come, first served' hypothesis) nevertheless there is no difference in the rate of hormone secretion from the two pools, and hydrolysis in both pools is affected by TSH.

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