Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020505 (hyperphagia)
 6,116 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypothalamic tissue levels of nine regulatory peptides (bombesin, calcitonin gene-related peptide [CGRP], galanin, neuromedin B, neuropeptide Y [NPY], neurotensin, somatostatin, substance P, and vasoactive intestinal peptide [VIP]) were compared in Aston obese diabetic (ob/ob) and lean (+/?) mice aged 4, 16, and 28 weeks. Neurotensin concentrations were significantly lower in ob/ob mice than in lean mice, with a 20% reduction (P = .03) in the whole hypothalamus at 4 weeks of age, a 24% reduction (P = .009) in the lateral hypothalamus at 16 weeks, and a 50% reduction (P = .0007) in the central hypothalamus at 28 weeks of age. Apart from a 42% increase in vasoactive intestinal peptide concentrations in the central hypothalamus of ob/ob mice at 28 weeks (P = .02), levels of the other eight peptides examined did not differ significantly between obese and lean groups. Neurotensin is known to cause anorexia and increased energy expenditure when injected into the central hypothalamus. Reduced hypothalamic neurotensin concentrations may reflect reduced neurotensinergic activity, which might contribute to hyperphagia and decreased energy expenditure, two major defects that contribute to obesity and diabetes in the ob/ob syndrome.
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PMID:Reduced hypothalamic neurotensin concentrations in the genetically obese diabetic (ob/ob) mouse: possible relationship to obesity. 194 36

The obese hyperglycaemic ob/ob mouse exhibits hyperphagia and other abnormalities of hypothalamic function. We measured hypothalamic concentrations of four peptides implicated in the control of appetite and energy expenditure, neuropeptide-Y (NPY), neurotensin, galanin, and somatostatin, by RIA and their respective mRNAs using semiquantitative Northern blotting. Using lean (+/+) mice as controls, we found unchanged concentrations of NPY, galanin, and somatostatin and a 25% reduction in neurotensin (P < 0.01). Neurotensin mRNA was similarly decreased (by 30%; P < 0.02), while NPY mRNA was increased 3-fold (P < 0.01). Centrally administered neurotensin decreases food intake, whereas NPY potently stimulates food intake. An increase in NPY gene expression together with reductions in neurotensin concentration and mRNA in the hypothalamus may be implicated in the development of hyperphagia and other neuroendocrine abnormalities seen in the ob/ob mouse.
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PMID:Increased neuropeptide-Y messenger ribonucleic acid (mRNA) and decreased neurotensin mRNA in the hypothalamus of the obese (ob/ob) mouse. 768 36

Neurotensin plays a role in regulating feeding behavior. Central injection of neurotensin reduces food intake and the anorectic effect of neurotensin is mediated through neurotensin receptor 1 (Ntsr1). Ntsr1-deficient mice are characterized by mild hyperphagia and overweight without hyperleptinemia. The mechanism by which Ntsr1-deficient mice develop these metabolic abnormalities is not well understood. Leptin, secreted by adipocytes, regulates food intake by acting on hypothalamic neurons including neurotensin-producing neurons. Since the anorectic effect of leptin is blocked by neurotensin receptor antagonist, we hypothesized that the anorectic effect of leptin is mediated through Ntsr1 in the central nervous system and that decreased sensitivity to the anorectic effect of leptin contributes to metabolic perturbations in Ntsr1-deficient mice. To address this hypothesis, we examined the effect of intracerebroventricular (i.c.v.) administration of leptin on food intake in Ntsr1-deficient mice. A single i.c.v. injection of leptin caused robust reductions in food intake in wild-type mice. These effects were markedly attenuated in Ntsr1-deficient mice. These data are consistent with our hypothesis that the anorectic effect of leptin is at least partly mediated through central Ntsr1 and that the leptin-Ntsr1 signaling pathway is involved in the regulation of food intake. Our data also suggest that the lack of Ntsr1 reduces sensitivity to the anorectic action of leptin, causing hyperphagia and abnormal weight gain.
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PMID:Impaired anorectic effect of leptin in neurotensin receptor 1-deficient mice. 1863 88

MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate gene expression post-transcriptionally. MiRNAs are implicated in various biological processes associated with obesity, including adipocyte differentiation and lipid metabolism. We used a neuronal-specific inhibition of miRNA maturation in adult mice to study the consequences of miRNA loss on obesity development. Camk2a-CreERT2 (Cre+) and floxed Dicer (Dicerlox/lox) mice were crossed to generate tamoxifen-inducible conditional Dicer knockouts (cKO). Vehicle- and/or tamoxifen-injected Cre+;Dicerlox/lox and Cre+;Dicer+/+ served as controls. Four cohorts were used to a) measure body composition, b) follow food intake and body weight dynamics, c) evaluate basal metabolism and effects of food deprivation, and d) assess the brain transcriptome consequences of miRNA loss. cKO mice developed severe obesity and gained 18 g extra weight over the 5 weeks following tamoxifen injection, mainly due to increased fat mass. This phenotype was highly reproducible and observed in all 38 cKO mice recorded and in none of the controls, excluding possible effects of tamoxifen or the non-induced transgene. Development of obesity was concomitant with hyperphagia, increased food efficiency, and decreased activity. Surprisingly, after reaching maximum body weight, obese cKO mice spontaneously started losing weight as rapidly as it was gained. Weight loss was accompanied by lowered O2-consumption and respiratory-exchange ratio. Brain transcriptome analyses in obese mice identified several obesity-related pathways (e.g. leptin, somatostatin, and nemo-like kinase signaling), as well as genes involved in feeding and appetite (e.g. Pmch, Neurotensin) and in metabolism (e.g. Bmp4, Bmp7, Ptger1, Cox7a1). A gene cluster with anti-correlated expression in the cerebral cortex of post-obese compared to obese mice was enriched for synaptic plasticity pathways. While other studies have identified a role for miRNAs in obesity, we here present a unique model that allows for the study of processes involved in reversing obesity. Moreover, our study identified the cortex as a brain area important for body weight homeostasis.
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PMID:A neuron-specific deletion of the microRNA-processing enzyme DICER induces severe but transient obesity in mice. 2562 59