Neuroendocrine Control of the Thymic Microenvironment: Role of Pituitary Hormones

Author(s):  
Wilson Savino ◽  
Valeria Mello-Coelho ◽  
Mireille Dardenne
2009 ◽  
Vol 2009 ◽  
pp. 1-13 ◽  
Author(s):  
M. K. Gill-Sharma

In the last 20 years, a pituitary-hypothalamus tissue culture system with intact neural and portal connections has been developed in our lab and used to understand the feedback mechanisms that regulate the secretions of adenohypophyseal hormones and fertility of male rats. In the last decade, several in vivo rat models have also been developed in our lab with a view to substantiate the in vitro findings, in order to delineate the role of pituitary hormones in the regulation of fertility of male rats. These studies have relied on both surgical and pharmacological interventions to modulate the secretions of gonadotropins and testosterone. The interrelationship between the circadian release of reproductive hormones has also been ascertained in normal men. Our studies suggest that testosterone regulates the secretion of prolactin through a long feedback mechanism, which appears to have been conserved from rats to humans. These studies have filled in a major lacuna pertaining to the role of prolactin in male reproductive physiology by demonstrating the interdependence between testosterone and prolactin. Systemic levels of prolactin play a deterministic role in the mechanism of chromatin condensation during spermiogenesis.


Author(s):  
М. Голубева

Введение. Изменение реологических свойств крови характерно для различных заболеваний, многие из которых связаны с нарушением реологии и, прежде всего, с изменением агрегации эритроцитов. Целью исследования было сравнение влияния малых регуляторных пептидов, являющихся фрагментами нейрогормонов, на агрегацию эритроцитов и тромбоцитов под действием адреналина в экспериментах in vitro. Материалы и методы. Эксперименты проводили на белых беспородных крысах-самцах, массой тела 180-200 г. Использовали пептиды, представляющие собой С-концевые фрагменты вазопрессина (Pro-Arg-Gly-NH2) и окситоцина (Pro-Leu-Gly-NH2). Результаты. Показано, что малые регуляторные пептиды, являющиеся продуктами протеолиза нейропептидов, оказывают существенное влияние на агрегатное состояние клеток крови. При сравнении влияния пептидов на агрегацию клеток крови, стимулированную адреналином, установлено, что фрагмент вазопрессина Pro-Arg-Gly-NH2 вызывал достоверное усиление агрегации как эритроцитов, так и тромбоцитов; тогда как фрагмент окситоцина Pro-Leu-Gly-NH2 ингибировал только агрегацию эритроцитов, не изменяя агрегации тромбоцитов. Заключение. Изучение путей поэтапного протеолиза пептидов может привести к разработке новых препаратов для направленной коррекции различных нарушений в организме, поэтому изучение эффектов С-концевых фрагментов гипофизарных гормонов на гемостаз является актуальным. Introduction. The changing of blood rheological properties is typical for various diseases; many of them are associated with rheology disorder and primarily with change of erythrocytes aggregation. The aim was to compare the effect of small regulatory peptides (fragments of neurohormones) on the aggregation of erythrocytes and platelets under adrenaline action in experiments in vitro. Materials and methods. Experiments were conducted on white outbred male rats, body weight 180-200 g. We used 2 peptides – C-terminal fragments of vasopressin (Pro-Arg-Gly-NH2) and oxytocin (Pro-Leu-Gly-NH2). Results. It was shown that small regulatory peptides (they are products of neuropeptides proteolysis) had a significant effect on blood cells aggregation. We compared the peptides effect on blood cells aggregation stimulated by adrenaline. It was found that vasopressin fragment Pro-Arg-Gly-NH2 significantly increased both erythrocytes and platelets aggregation, while oxytocin fragment Pro-Leu-Gly-NH2 inhibited only erythrocytes aggregation without changing of platelet aggregation. Conclusion. Investigation of phased peptides proteolysis may result in the development of new drugs for targeted correction of various disturbances. So it is of current interest to study the effects of C-terminal fragments of pituitary hormones on hemostasis.


Neurosurgery ◽  
1984 ◽  
Vol 14 (4) ◽  
pp. 499-504
Author(s):  
Lincoln F. Ramirez ◽  
Allan B. Levin

Abstract Thirteen series of patients who underwent surgical or chemical hypophysectomy for the relief of pain associated with cancer were reviewed. In 10 series, involving 334 patients with breast or prostate cancer, surgical hypophysectomy produced pain relief in 70% of the patients afflicted with either tumor, including some with no evidence of hormone dependence. These results were then compared with the results of chemical hypophysectomy. This procedure was performed in 3 series involving 533 patients, of whom 24% had cancer other than breast or prostate. Chemical hypophysectomy produced pain relief in over 75% of the patients, regardless of tumor type or hormonal dependence. The possible role of the pituitary, the hypothalamus, and endogenous opiates in mediating the pain relief associated with hypophysectomy was examined. The mechanism by which pain relief is achieved remains unclear, but there is significant evidence that this relief is not related directly to the expected fall in the levels of known pituitary hormones. Evidence is provided that pain relief is the result of a hypothalamic pain-suppressing capability triggered by hypophy-sectomy. On the basis of both clinical data and the mechanism of action, we conclude that surgical and chemical hypophysectomy are fundamentally similar procedures.


Endocrinology ◽  
2005 ◽  
Vol 146 (1) ◽  
pp. 156-163 ◽  
Author(s):  
V. M. Navarro ◽  
J. M. Castellano ◽  
R. Fernández-Fernández ◽  
S. Tovar ◽  
J. Roa ◽  
...  

Loss-of-function mutations of the gene encoding GPR54, the putative receptor for the KiSS-1-derived peptide metastin, have been recently associated with hypogonadotropic hypogonadism, in both rodents and humans. Yet the actual role of the KiSS-1/GPR54 system in the neuroendocrine control of gonadotropin secretion remains largely unexplored. To initiate such analysis, the effects of KiSS-1 peptide on LH secretion were monitored using in vivo and in vitro settings under different experimental conditions. Central intracerebroventricular administration of KiSS-1 peptide potently elicited LH secretion in vivo over a range of doses from 10 pmol to 1 nmol. The effect of centrally injected KiSS-1 appeared to be mediated via the hypothalamic LHRH. However, no effect of central administration of KiSS-1 was detected on relative LHRH mRNA levels. Likewise, systemic (ip and iv) injection of KiSS-1 markedly stimulated LH secretion. This effect was similar in terms of maximum response to that of central administration of KiSS-1 and might be partially attributed to its ability to stimulate LH secretion directly at the pituitary. Finally, the LH-releasing activity of KiSS-1 was persistently observed after blockade of endogenous excitatory amino acid and nitric oxide pathways, i.e. relevant neurotransmitters in the neuroendocrine control of LH secretion. In summary, our results provide solid evidence for a potent stimulatory effect of KiSS-1 on LH release, acting at central levels (likely the hypothalamus) and eventually at the pituitary, and further document a novel role of the KiSS-1/GPR54 system as a relevant downstream element in the neuroendocrine network governing LH secretion.


Author(s):  
B.E. Reubinoff ◽  
S. Mor-Yosef ◽  
A. Shushan ◽  
A. Brzezinski ◽  
V. Tanos ◽  
...  

2008 ◽  
Vol 40 (5-6) ◽  
pp. 393-403 ◽  
Author(s):  
L. A. Bondarenko ◽  
N. N. Sotnik ◽  
A. R. Gevorkyan

PPAR Research ◽  
2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Bettina König ◽  
Christine Rauer ◽  
Susann Rosenbaum ◽  
Corinna Brandsch ◽  
Klaus Eder ◽  
...  

PPAR is a lipid-activable transcription factor that mediates the adaptive response to fasting. Recent data indicate an important role of brain PPAR in physiological functions. However, it has not yet been shown whether PPAR in brain can be activated in the fasting state. Here we demonstrate that fasting of rats increased mRNA concentrations of typical PPAR target genes implicated in -oxidation of fatty acids (acyl-CoA oxidase, carnitine palmitoyltransferase-1, medium chain acyl-CoA dehydrogenase) and ketogenesis (mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase) in pituitary gland and partially also in frontal cortex and diencephalon compared to nonfasted animals. These data strongly indicate that fasting activates PPAR in brain and pituitary gland. Furthermore, pituitary prolactin and luteinizing hormone- mRNA concentrations were increased upon fasting in wild-type mice but not in mice lacking PPAR. For proopiomelanocortin and thyrotropin-, genotype-specific differences in pituitary mRNA concentrations were observed. Thus, PPAR seems to be involved in transcriptional regulation of pituitary hormones.


2021 ◽  
Vol 12 ◽  
Author(s):  
Irina N. Trofimova ◽  
Anastasia A. Gaykalova

This review highlights the differential contributions of multiple neurochemical systems to temperament traits related and those that are unrelated to emotionality, even though these systems have a significant overlap. The difference in neurochemical biomarkers of these traits is analysed from the perspective of the neurochemical model, Functional Ensemble of Temperament (FET) that uses multi-marker and constructivism principles. Special attention is given to a differential contribution of hypothalamic–pituitary hormones and opioid neuropeptides implicated in both emotional and non-emotional regulation. The review highlights the role of the mu-opioid receptor system in dispositional emotional valence and the role of the kappa-opioid system in dispositional perceptual and behavioural alertness. These opioid receptor (OR) systems, microbiota and cytokines are produced in three neuroanatomically distinct complexes in the brain and the body, which all together integrate dispositional emotionality. In contrast, hormones could be seen as neurochemical biomarkers of non-emotional aspects of behavioural regulation related to the construction of behaviour in fast-changing and current situations. As examples of the role of hormones, the review summarised their contribution to temperament traits of Sensation Seeking (SS) and Empathy (EMP), which FET considers as non-emotionality traits related to behavioural orientation. SS is presented here as based on (higher) testosterone (fluctuating), adrenaline and (low) cortisol systems, and EMP, as based on (higher) oxytocin, reciprocally coupled with vasopressin and (lower) testosterone. Due to the involvement of gonadal hormones, there are sex and age differences in these traits that could be explained by evolutionary theory. There are, therefore, specific neurochemical biomarkers differentiating (OR-based) dispositional emotionality and (hormones-based) body’s regulation in fast-changing events. Here we propose to consider dispositional emotionality associated with OR systems as emotionality in a true sense, whereas to consider hormonal ensembles regulating SS and EMP as systems of behavioural orientation and not emotionality.


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