Feeding during the resting phase causes gastrointestinal tract dysfunction and desynchronization of metabolic and neuronal rhythms in rats.

BACKGROUND: Disrupted circadian rhythms may result from a misalignment between the environmental cycles (due to shift work, sleep restriction, feeding at an unusual time of day) and endogenous rhythms or by physiological aging. Among the numerous adverse effects, disrupted rhythms affect the brain-gut axis, contributing to the pathogenesis of several diseases in the gastrointestinal tract, for example, abdominal pain, constipation, gastric dyspepsia, inflammatory bowel disease, irritable bowel syndrome, and others. METHODS: This study evaluated the rat gastric emptying, gastrointestinal motility, a clock gene, gut hormones, and the neuron activity on the nucleus of tractus solitarius (NTS), area postrema (AP), and the dorsal motor nucleus of the vagus (DMV) in rats with restricted food access to the rest phase for 4 weeks. KEY RESULTS: Our results show that food restricted to the rest light period disturbed the expression pattern of a series of transcripts, including metabolic and circadian regulation. Also, the secretion of gastrointestinal hormones, gastric emptying, intestinal motility, and NTS, AP, and DMV activity were altered. CONCLUSIONS & INFERENCES: These data indicate the importance of the time of the day food is ingested on the regulation of energy balance and the endocrine activity of the stomach and small intestine, emphasizing the importance of food as a powerful circadian synchronizer and an essential factor for the triggering of gastrointestinal diseases and metabolic problems. These findings offer a novel clue regarding the obesity-promoting effect attributed to feeding time and open the possibility of treating this and other intestinal disorders.

Appetite-regulating hormones from the upper gut: disrupted control of xenin and ghrelin in night workers.

OBJECTIVE: Shift work is associated with circadian rhythm disorder, impaired sleep and behavioural changes, including eating habits, predisposing to obesity and metabolic dysfunctions. It involves a neuro-hormonal dysregulation of appetite towards positive energy balance, including increased ghrelin and decreased leptin, but little is known about other hormones, such as xenin, derived from the upper gut (like ghrelin), and lower gut hormones. Our objective was to compare night workers with day workers in relation to appetite-regulating hormones and other metabolic parameters. DESIGN: Cross-sectional, observational study. PARTICIPANTS: Twenty-four overweight women, divided into night shift workers (n = 12) and day shift workers (n = 12). MEASUREMENTS: BMI, waist circumference, fat mass percentage; diet composition; Pittsburgh Sleep Quality Index; lipids; adipokines; meal tolerance test curves of glucose, insulin, ghrelin, PYY3-36, oxyntomodulin, xenin, GLP-1; insulin sensitivity (Stumvoll index). RESULTS: Night workers, as compared with day workers, had greater body fat mass percentage and tendency to greater waist circumference despite similar BMI; greater energy intake; impaired sleep; lower insulin sensitivity; increased triglycerides and tendency to increased C-reactive protein; similar levels of leptin and other adipokines. Night workers had a blunted post-meal suppression of ghrelin (AUCi(0-60 min) 19·4 ± 139·9 vs -141·9 ± 9·0 ng/ml·60 min, P < 0·01); blunted rise of xenin (AUC(0-180 min) 8690·9 ± 2988·2 vs 28 504·4 ± 20 308·3 pg/ml·180 min, P < 0·01) and similar curves of PYY3-36, oxyntomodulin and GPL-1. CONCLUSION: Compared with day workers within the same BMI range, night workers presented a disrupted control of ghrelin and xenin, associated with behavioural changes in diet and sleep and increased adiposity and related metabolic alterations.

Gastrina: hormona de múltiples funciones / Gastrin: multifunctional hormone

Gastrin is a polypeptide hormone secreted primarily by G cells of the gastric antrum. Its main function is the regulation of gastric acidity, through the release of histamine, which ultimately acts on the parietal cell. There are a number of pathological conditions characterized by persistent hypergastrinemia will cause various effects, from peptic disease to cancer. Most research points to clarify their involvement in processes of proliferation of different cell types and thus to find a treatment for cancer. Intermediates molecules have been described for the metabolism of gastrin, which also possess the property of stimulating the proliferation of various cell lines and participated in processes of cell migration and invasion. Using molecular bioengineering has been able to modify the original molecule to create receptor antagonist and thus able to address some of the associated diseases. Much of this hormone, described over a century ago, is still unknown (AU)

Hypothalamic regulation of food intake and clinical therapeutic applications.

Current estimates suggest that over 1 billion people are overweight and over 300 million people are obese. Weight gain is due to an imbalance between energy expenditure and dietary intake. This review discusses the hypothalamic control of appetite and highlights key developments in research that have furthered our understanding of the complex pathways involved. Nuclei within the hypothalamus integrate peripheral signals such as adiposity and caloric intake to regulate important pathways within the central nervous system controlling food intake and energy expenditure. Firmly established pathways involve the orexigenic NPY/AgRP and the anorexigenic POMC/CART neurons in the arcuate nucleus (ARC) of the hypothalamus. These project from the ARC to other important hypothalamic nuclei, including the paraventricular, dorsomedial, ventromedial and lateral hypothalamic nuclei. In addition there are many projections to and from the brainstem, cortical areas and reward pathways, which modulate food intake.

Hypothalamic regulation of food intake and clinical therapeutic applications: [review] / Regulação hipotalâmica da ingestão alimentar e suas aplicações terapêuticas clínicas: [revisão]

Current estimates suggest that over 1 billion people are overweight and over 300 million people are obese. Weight gain is due to an imbalance between energy expenditure and dietary intake. This review discusses the hypothalamic control of appetite and highlights key developments in research that have furthered our understanding of the complex pathways involved. Nuclei within the hypothalamus integrate peripheral signals such as adiposity and caloric intake to regulate important pathways within the central nervous system controlling food intake and energy expenditure. Firmly established pathways involve the orexigenic NPY/AgRP and the anorexigenic POMC/CART neurons in the arcuate nucleus (ARC) of the hypothalamus. These project from the ARC to other important hypothalamic nuclei, including the paraventricular, dorsomedial, ventromedial and lateral hypothalamic nuclei. In addition there are many projections to and from the brainstem, cortical areas and reward pathways, which modulate food intake.

As estimativas atuais sugerem que mais de 1 bilhão de pessoas apresentam sobrepeso e 300 milhões são obesas. O ganho de peso representa um desequilíbrio entre o gasto energético e o consumo alimentar. Esta revisão discute o controle hipotalâmico do apetite e destaca os pontos-chave no desenvolvimento de pesquisas para ampliar o nosso entendimento dos complexos mecanismos envolvidos nesta regulação. Núcleos situados no hipotálamo integram uma série de sinais com o sistema nervoso central controlando a ingestão alimentar e o gasto energético. As vias mais estabelecidas envolvem os neurônios orexigênicos NPY/AgRP e os neurônios anorexigênicos POMC/CART no núcleo arqueado (ARC) do hipotálamo. Esses neurônios se projetam do ARC para outros importantes núcleos hipotalâmicos, tais quais: paraventricular, dorsomedial, ventromedial e lateral. Além disso, existem várias projeções que vão e vem do tronco cerebral, das áreas corticais e das vias de retroalimentação que modulam o consumo alimentar.

Central nervous system circuitry involved in the hyperinsulinism syndrome.

Raised plasma levels of insulin, glucose and glucagon are found in patients affected by 'hyperinsulinism'. Obesity, hypertension, mammary plus ovary cysts and rheumatic symptoms are frequently observed in these patients. Sleep disorders and depression are also present in most subjects affected by this polysymptomatic disorder. The simultaneous increases of glucose, insulin and glucagon plasma levels seen in these patients indicate that the normal crosstalk between A cells, B cells and D cells is disrupted. With respect to this, it is well known that glucose excites B cells (which secrete insulin) and inhibits A cells (which secrete glucagon), which in turn excites D cells (which secrete somatostatin). Gastrointestinal hormones (incretins) modulate this crosstalk both directly and indirectly throughout pancreatic and hepatobiliary mechanisms. The above factors depend on autonomic nervous system mediation. For instance, acetylcholine released from parasympathetic nerves excites both B and A cells. Noradrenaline released from sympathetic nerves and adrenaline secreted from the adrenal glands inhibit B cells and excite A cells, which are crowded with beta(2)- and alpha(2)-receptors, respectively. Noradrenaline released from sympathetic nerves also excites A cells by acting at alpha(1)-receptors located at this level. According to this, the excessive release of noradrenaline from these nerves should provoke an enhancement of glucagon secretion which will result in overexcitation of insulin secretion from B cells. That is the disorder seen in the so-called 'hyperinsulinism', in which raised plasma levels of glucose, insulin and glucagon coexist. Taking into account that neural sympathetic activity is positively correlated to the A5 noradrenergic nucleus and median raphe serotonergic neurons, and negatively correlated to the A6 noradrenergic, the dorsal raphe serotonergic and the C1 adrenergic neurons, we postulate that this unbalanced central nervous system circuitry is responsible for the hyperinsulinism syndrome.

[Gastrointestinal hormones]. / Hormonas gastrointestinales.

Recently, knowledge about the physiological and physiopathological role of some already known gastrointestinal hormones has been increased. At the same time, new biologically active substances (peptides) have been isolated from the gastrointestinal tract and pancreas. Some hormones that were thought to be restricted to the digestive system have been identified in the brain and some peptides localized in the nervous terminals in the myenteric plexuses, actively participate in the biological process of the gut. These findings have made the comprehension of this field more complicated. As a consequence of this, the term of "gastrointestinal endocrinology" is emerging. In this article we will discuss some general concepts of gastrointestinal and pancreatic hormonal physio-pathology and individually, about the role of some hormones and peptides in the normal and abnormal biological process. We emphasize the importance of biochemical diagnosis of those abnormalities.

Endocrinología gastroenterológica: aspectos básicos / Gastrointestinal endocrinology: basic aspects

El presente artículo revisa los aspectos básicos y generales de la endocrinología del tracto gastrointestinal, conocimientos que facilitan la comprensión de sus aspectos fisiológicos y clínicos. Las células del tracto digestivo producen diversos mensajeros químicos que son liberados por mecanismos endocrinos, neurocrinos y paracrinos; la interrelación de estos eventos hormonales con eventos neuronales, van a regular los procesos de absorción, secreción, y de motilidad digestiva

[Gastroenterologic endocrinology: basic aspects]. / Endocrinología gastroenterológica: aspectos básicos.

Gastrointestinal cells produce several substances which act as messengers in the various biochemical processes of the body. These substances are released by endocrine, paracrine and neurocrine mechanisms. Both, hormonal and neuronal phenomenaregulate the absorptive, secretory and motility activity of the gastrointestinal tract. This paper goes over basic and general aspects of hormones secreted in the gastrointestinal system in order to make easier the understanding of their influence in the health and disease.

Neuro-hormônios do trato gastrintestinal / Neurohormones of the gastrointestinal tract

Os autores fazem um breve estudo acerca da neuroendocrinologia do tubo digestivo. Verificam que diversos hormônios podem potencializar ou inibir açöes fisiológicas agindo sobre um órgäo-alvo comum, situado no trato gastrintestinal. Constatam também a existência de síndromes poliendócrinas capazes de produzir níveis séricos elevados de praticamente todos os peptídeos citados, ampliando-se o conceito e extensäo do sistema APUD. Concluem que o mecanismo etiopatogênico de diversas doenças gastrintestinais näo admite explicaçöes simplistas, ou o emprego de práticas terapêuticas, clínicas ou cirúrgicas tidas como definitivas, pois as anormalidades encontradas na estrutura fisiológica do tubo digestivo estäo relacionadas a distúrbios hormonais complexos e ainda obscuros em vários pontos pesquisados