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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ghrelin has a correlation with insulin secretion, beta-cell development, and diabetes in crucial development period. The aim of this study was to compare the changes in plasma ghrelin, insulin, and glucose concentrations, and variation of ghrelin expression in the pancreas in response to intrauterine malnutrition in newborn rats. Pregnant rats at day 2 were randomly divided into two groups: nourished (fed ad libitum; NR) and undernourished rats (UR). The offspring of NR were defined as normal-birth-weight group (NBW, n = 79) and those of UR were defined as low-birth-weight group (LBW, n = 74). Plasma glucose, ghrelin, and serum insulin of both dams and their pups were analyzed at the first day after birth. The entire pancreas was collected for determination of ghrelin and insulin mRNAs, and quantification of pancreas ghrelin and insulin. Immunohistochemical double staining and confocal microscopy were performed on rat pancreas. Birth weight was 5.81 +/- 0.64 and 4.76 +/- 0.23 g in NBW group and LBW group respectively. Fasting plasma ghrelin concentrations in UR group (1382 (1287-1513) pg/ml) were higher than that of NR group (1072 (974-1205) pg/ml). Plasma ghrelin concentrations in the LBW group (2176 (2031-2384) pg/ml) were significantly lower than that of the NBW group (2493 (2311-2675) pg/ml). Undernutrition caused a decrease in plasma insulin concentrations in both UR dams and LBW pups (P < 0.001). Ghrelin mRNA and total ghrelin of pancreas were significantly affected by intrauterine nutrition state. Pancreas insulin concentrations were significantly affected by intrauterine nutrition (P = 0.007). The majority of ghrelin-producing cells were present at the periphery of islets in the NBW group. Ghrelin was colocalized with insulin in ss-cells in LBW group. The percentage of ghrelin-positive cells in the islets of LBW group was significantly higher than that of the NBW group (P < 0.01). Intrauterine undernutrition may affect the birth weight, plasma insulin and ghrelin levels, islet ghrelin expression, and ghrelin cell distribution. It will be interesting to investigate intrauterine nutrition which is involved in islet ghrelin expression and ghrelin cell distribution.
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PMID:The effects of intrauterine undernutrition on pancreas ghrelin and insulin expression in neonate rats. 1759 26

Endothelial dysfunction is thought to be a major cause of vascular complications in diabetes. Our research shows that ghrelin attenuates high glucose-induced apoptosis in cultured human umbilical vein endothelial cells (ECV-304). Exposure to glucose (33.3mM) for 72 h caused a significant increase in apoptosis, as evaluated by TUNEL and flow cytometry, but pretreatment of ghrelin (10(-7)M) eliminated high glucose-induced apoptosis in ECV-304. Ghrelin also prevented the induction of caspase-3 activation, in cells incubated with glucose (33.3 mM). Exposure of cells to ghrelin (10(-7)M) caused rapid activation of Akt. PI3K inhibitor, LY294002 attenuated ghrelin's inhibitory effect on caspase-3 activity. Ghrelin protected endothelial cells from high glucose by inhibiting reactive oxygen species (ROS) generation. Results of our study indicate that ghrelin inhibits both high glucose-induced apoptosis via PI3K/Akt pathway and ROS production in ECV-304. This peptide may have potential in preventing diabetic complications, especially in obese patients.
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PMID:Effect of ghrelin on human endothelial cells apoptosis induced by high glucose. 1771 61

Ghrelin, an acylated 28-amino-acid peptide, is an endogenous ligand of the growth hormone secretagogue type 1a (GHS-R1a). Ghrelin is best known for its hypothalamic actions on growth hormone-releasing hormone neurons and neuropeptide Y/agouti-related peptide neurons; however, ghrelin affects multiple organ systems and the complexity of its functions is only now being realized. Although ghrelin is mainly produced in the stomach, it is also produced in low levels by the hypothalamus and by most peripheral tissues. GHS-R1a is expressed predominantly in the anterior pituitary gland, at lower levels in the brain including hypothalamic neurons that regulate feeding behavior and glucose sensing, and at even lower levels in the pancreas. A reciprocal relationship exists between ghrelin and insulin, suggesting that ghrelin regulates glucose homeostasis. Ablation of ghrelin in mice increases glucose-induced insulin secretion, and improves peripheral insulin sensitivity. This review focuses on the newly emerging role of ghrelin in glucose homeostasis and exploration of whether ghrelin is a potential therapeutic target for diabetes.
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PMID:Central and peripheral roles of ghrelin on glucose homeostasis. 1789 34

Bilateral lesions of the hypothalamic paraventricular nuclei (PVN) induce hyperphagia and obesity, and ghrelin stimulates appetite in rodents and humans. Conversely, corticotrophin-releasing hormone (CRH) and melanotan-II (MT-II, a synthetic structural homologue of alpha-melanocyte-stimulating hormone, alphaMSH) inhibit feeding behavior. The purpose of the present study was to determine whether these peptides are involved in the hyperphagia and obesity induced by PVN lesions. After bilateral electrolytic lesions of the PVN, rats were given ghrelin intraperitoneally (i. p.), or intracerebroventricular (i. c. v.) infusion of CRH or MT-II. We measured the cumulative food intake (FI) for 4 h after ghrelin injection in rats fed AD LIB, and the changes in FI at 15 min, 30 min, 1 h, and 2 h after infusion of CRH and MT-II in rats fasted for 24 h. Ghrelin significantly increased cumulative FI, with maximal response 3 h and 4 h after injection, and at these times, the FI of PVN-lesioned rats was greater than that of sham-operated rats. CRH significantly decreased FI in all experimental animals, but at 1 h, there was a more powerful inhibitory effect on FI in the PVN-lesioned group than in the sham-operated group. MT-II decreased FI in sham-operated, but not in PVN-lesioned rats. Thus, ghrelin and CRH showed more potent orexigenic and anorectic effects in PVN-lesioned rats, respectively, but MT-II lost its inhibitory action on feeding behavior. These results suggest that the hyperphagia and obesity induced by PVN lesions may be related to an increased orexigenic action of ghrelin due to the destruction of endogenous CRH and alphaMSH receptors.
Exp Clin Endocrinol Diabetes 2007 Nov
PMID:Effects of ghrelin, corticotrophin-releasing hormone, and melanotan-II on food intake in rats with paraventricular nucleus lesions. 1805 2

Insulin release from pancreatic islet beta-cells is stimulated by glucose. Glucose-induced insulin release is potentiated or suppressed by hormones and neural substances. Ghrelin, a novel acylated 28-amino acid peptide isolated from stomach, is the endogenous ligand for the growth hormone (GH) secretagogue-receptor (GHS-R). Circulating ghrelin is produced predominantly in stomach. Ghrelin is a potent stimulator of GH release and feeding as well as exhibiting positive cardiovascular effects. In relation to the glucose metabolism, initial studies indicated that low plasma ghrelin levels are associated with elevated fasting insulin levels, insulin resistance, and obesity. It has recently been demonstrated that ghrelin suppresses glucose-induced insulin release via G alpha(i2) subtype of GTP-binding proteins and delayed outward K(+) (Kv) channels, representing a novel signaling mechanism, and that the ghrelin originating from islets regulates insulin release and thereby glycemia. Furthermore, elimination of ghrelin enhances insulin release to prevent or ameliorate glucose intolerance in high-fat diet fed mice and ob/ob mice. This review focuses on the physiological roles of ghrelin in regulating insulin release and glycemia, the insulinostatic mechanisms of ghrelin in islet beta-cells, and the potential of ghrelin-GHS-R system as the therapeutic target to treat type 2 diabetes.
Curr Diabetes Rev 2008 Feb
PMID:Ghrelin regulates insulin release and glycemia: physiological role and therapeutic potential. 1822 Jun 91

Identification of ghrelin started with the discovery of growth hormone secretagogues, continued with the description of ghrelin receptors and ended with the elucidation of the chemical structure of ghrelin. However, several issues concerning the role of ghrelin in physiological and pathophysiological processes are still under investigation. Most of the ghrelin produced in the body is secreted in the stomach, but it is also expressed in the hypothalamus, pituitary, pancreas, intestine, kidney, heart and gonads. Ghrelin stimulates growth hormone secretion via growth hormone secretagogue receptors. Ghrelin secretion in the stomach depends on both acute and chronic changes in nutritional status and energy balance. Current data support the hypothesis that the stomach, in addition to its important role in digestion, not only influences pituitary hormone secretion but, via ghrelin production, it also sends orexigenic (appetite increasing) signals to hypothalamic nuclei involved in the regulation of energy homeostasis. In addition to these main effects, ghrelin influences insulin secretion and glucose metabolism and it may exert potentially important effects on cardiovascular and gastrointestinal functions. Because of its effects on a large number of physiological functions, ghrelin may be involved in the pathomechanism of several human disorders, including disturbances of appetite, energy homeostasis and glucose metabolism. Further research might lead to a better understanding of the pathophysiology of ghrelin and might provide more effective therapy for the above disorders.
Diabetes Metab Res Rev
PMID:Ghrelin: a new peptide regulating the neurohormonal system, energy homeostasis and glucose metabolism. 1835 May 24

Studying communication between the gut and the brain is as relevant and exciting as it has been since Pavlov's discoveries a century ago. Although the efferent limb of this communication has witnessed significant advances, it is the afferent, or sensory, limb that has recently made for exciting news. It is now clear that signals from the gut are crucial for the control of appetite and the regulation of energy balance, glucose homeostasis, and more. Ghrelin, discovered just a few years ago, is the first gut hormone that increases appetite, and it may be involved in eating disorders. The stable analogue of glucagon-like peptide-1 has rapidly advanced to one of the most promising treatment options for type-2 diabetes. Changes in the signalling patterns of these and other gut hormones best explain the remarkable capacity of gastric bypass surgery to lower food intake and excess body weight. Given the enormous societal implications of the obesity epidemic, these are no small feats. Together with the older gut hormone cholecystokinin and abundant vagal mechanosensors, the gut continuously sends information to the brain regarding the quality and quantity of ingested nutrients, not only important for satiation and meal termination, but also for the appetitive phase of ingestive behaviour and the patterning of meals within given environmental constraints. By acting not only on brainstem and hypothalamus, this stream of sensory information from the gut to the brain is in a position to generate a feeling of satisfaction and happiness as observed after a satiating meal and exploited in vagal afferent stimulation for depression.
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PMID:Vagal and hormonal gut-brain communication: from satiation to satisfaction. 1840 43

The various hormones, proteins and other compounds related to developing obesity, insulin resistance and type 2 diabetes are analyzed in the paper. 1) Leptin, ciliary neurutrophic factor, adiponectin, glucagon-like peptide 1, peptide YY, neuromedin S, as well as the protein receptors of these hormones decrease the food consumption, increase the energy turnover, and prevent obesity, insulin resistance, and type 2 diabetes development. The mediators of these hormone and receptor actions are melanocyte stimulating hormone (MSH), corticotropin-releasing hormone (CRH), and the others. 2) Ghrelin, endogenose cannabinoides, galanin-like peptide and the mediators of their actions: neuropeptide Y (NPY) and Agouti gene related protein (AGRP) increase the appetite and food consumption. Peroxisome proliferation-activated receptor (PPAR) performs the similar action on food intake. The activation of the first group compound functioning decreases the obesity, increases the energy turnover, facilitates the insulin action and prevents the insulin resistance and type 2 diabetes. Increasing the activities of the second group, as well as, decreasing the actions of the first one of substances induce the opposite effects and facilitate obesity, insulin resistance, and type 2 diabetes developments. The interconnections of the molecular mechanisms of so many hormone actions make the very complicated tusk to study the various endocrine disorders including diabetes mellitus as well.
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PMID:[The interconnections of molecular mechanisms of hormone actions and their role in pathogenesis of obesity, insulin resistance, and diabetes mellitus]. 1842 6

Plasminogen activator inhibitor type 1 (PAI-1), produced partly from liver is a risk factor for macrovascular and microvascular complications of diabetes. Ghrelin, a recently described orexigenic peptide hormone, attenuates PAI-1 induced by TNF-alpha in the human hepatoma cell line (HepG2). Exposure to TNF-alpha (1 ng/ml) for 24h caused a significant increase in PAI-1 mRNA expression and protein secretion, as evaluated by RT-PCR and ELISA, but pretreatment with ghrelin (1-100 ng/ml) inhibited both basal and TNF-alpha-induced PAI-1 release in a dose and time-dependent manner in HepG2. PDTC, selective NF-kappaB inhibitor, had no additive inhibitory effects with ghrelin. The results indicate that ghrelin inhibits both basal and TNF-alpha-induced PAI-1 production via NF-kappaB pathway in HepG2 cells, and suggest that the peptide plays a therapeutic role in atherosclerosis, especially in obese patients with insulin resistance, in whom ghrelin levels were reduced.
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PMID:Ghrelin attenuates plasminogen activator inhibitor-1 production induced by tumor necrosis factor-alpha in HepG2 cells via NF-kappaB pathway. 1870 Jan 66

Effects of glucomannan as a supplementary treatment in type 2 diabetes mellitus were investigated by measuring ghrelin, leptin and insulin responses to OGTT. Glucomannan enhanced prandial ghrelin reduction when given before glucose load and impeded the rise of fasting ghrelin after 4-week supplement. Ghrelin-induced feeding may be attenuated by glucomannan.
Diabetes Res Clin Pract 2009 Feb
PMID:Immediate and long-term effects of glucomannan on total ghrelin and leptin in type 2 diabetes mellitus. 1910 25


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