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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The administration of monosodium-L-glutamate (MSG) during the neonatal period is known to result in central nervous system lesions in the arcuate nucleus of the hypothalamus and the retina. Rodents so treated exhibit behavioral deficts and endocrinopathies including obesity, hypogonadism, hypothyroidism, pituitary atrophy, tail automutilation and diminished locomotor activity. Assessment of endocrine status revealed normal serum levels of glucagon, thyroid-stimulating hormone and luteinizing hormone, and diminished levels of thyroid hormones and growth hormone in MSG-treated rats. Prolactin levels were elevated in the glutamate-treated male rats. Within the brain hypothalamic levels of thyrotropin-releasing hormone, luteinizing hormone-releasing hormone, and somatostatin were unchanged. Measurement of neurotransmitters and neurotransmitter-related enzymes in individual hypothalamic nuclei derived from MSG-treated rats revealed normal levels of norepinephrine, serotonin and glutamic acid decarboxylase, but reduced levels of choline acetyltransferase and dopamine in the arcuate nucleus and median eminence. Histochemical methods for visualization of dopamine and acetylcholinesterase in the mediobasal hypothalamus confirmed these findings. The MSG-treated animals exhibited a normal diurnal rhythm of pineal serotonin N-acetyltransferase activity. These data indicate that the MSG-induced endocrine deficiency syndrome results at least partly from destruction of cholinergic and dopamingeric tuberoinfundibular systems in the hypothalamus.
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PMID:Models of neuroendocrine regulation: use of monosodium glutamate as an investigational tool. 3 35

Lipid mobilizing substances (LMS) are present in the hypothalamus and pituitary of mammals and probably are involved in the central neural control of obesity. Most of these have direct lipolytic effects, like lipid mobilizing factor (LMF) and LH-RH from the hypothalamus as well as lipotropin (LPH), melanocyte-stimulating hormone (MSH), corticotropin (ACTH), and growth hormone (GH) from the pituitary gland. Some of the substances, like GH-release inhibiting hormone (GH-RIH), affect lipolysis by secondary actions on pancreatic hormones such as insulin and glucagon. Other hypothalamic hormones, like GH-releasing hormone (GH-RH) may influence lipolysis secondarily through the pituitary hormones (e.g. GH) whose release they control. Regardless of how lipid mobilization is affected, investigations into the problem of obesity should take these LMS into consideration.
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PMID:Lipid mobilizing hormones of the hypothalamus and pituitary. 17 3

Obese Zucker rats were either pair-fed to their lean litter-mates or fed ad lib, to determine the effect of hyperphagia on serum hormone levels and tissue metabolism as indicated by enzyme activities and in vitro metabolite flux. Hyperphagia was shown to be non-essential for the elevation in serum insulin and suppression in serum growth hormone and prolactin in the genetically obese rat. It was also shown that the increased liver cell lipogenic rate was not dependent on hyperphagia in the obese rat and that adipose cell lipogenesis was not significantly altered in the pair-fed obese rat. The utilization of alanine for glucose synthesis in vitro was similar for both lean and obese rats, but its utilization for fatty acid synthesis was higher in the obese rat. Data is presented which suggest that the inhibitory effect of glucagon on liver lipogenesis is blunted in the obese rat.
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PMID:Serum hormone levels and tissue metabolism in pair-fed lean and obese Zucker rats. 19 81

Several characteristics of the binding of insulin and glucagon to human circulating mononuclear leukocytes have been studied. Functional analysis (latex bead ingestion) revealed that cell mixtures, as prepared according to Boyum and used generally in studies of insulin resistance in humans, consist of 20-29% phagocytic monocytes, with the remainder being lymphocytes. Partial separation of monocytes from lymphocytes on columns of Sephadex G-10, followed by correlation of insulin binding with cell type, confirms that the monocyte is the binding species. Insulin influenced neither glucose uptake nor the further conversion of glucose to lipids and CO2 by the leukocytes. The transport of alpha-aminoisobutyrate, a nonmetabolizable amino acid, into these cells was also unaffected by insulin. Monocyte/lymphocyte mixtures specifically bound glucagon and prostaglandin E1. At physiological concentrations of these hormones, steady states were reached in 15 min and 45 min, respectively. In contrast to the 8-10-fold increases in cellular cyclic AMP produced by prostaglandins, the effect of glucagon was very small but apparently real. Under appropriate preincubation conditions, sodium azide and iodoacetamide inhibited phagocytosis and insulin binding in parallel. The binding of glucagon was unaffected by these agents. Although both antimycin A and actinomycin D inhibited phagocytosis of the monocytes, only the former inhibited insulin binding; there was only a slight effect on glucagon binding. We would conclude that the binding of insulin to human circulating monocytes, although reflective of insulin resistance in diabetes mellitus and obesity, may not be to traditional receptors. In contrast, the binding of glucagon to lymphocyte/monocyte mixtures may be to function-linked receptors.
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PMID:Hormone receptors: VI. On the nature of the binding of glucagon and insulin to human circulating mononuclear leukocytes. 20 May 11

The Zucker (fatty) rat is one of a group of animals that inherit obesity as an autosomal Mendelian recessive trait. These rats are obese, hyperphagic, and hyperinsulinemic, but blood glucose remains at normal levels. Although these rats eat more than normal rats, their response to the addition of adulterants to the food or after exposure to the cold is more like that of normal rats than rats with hypothalamic obesity. The hypertriglyceridemia which characterized these animals is due to the increased hepatic production of a very low density lipoproteins. Adipocytes are increased in size and in number with the subcutaneous fat depot showing the largest increase in the number of fat cells. Lipogenesis from glucose is brisk in the young animals but declines with age. Enzymatic patterns of glycolysis and gluconeogenesis appear to reflect the altered internal milieu rather than specific defects. Endocrine changes in the fatty rat include hyperinsulinemia, reduced levels of glucagon, hypothyroidis, and impaired reproductive function. A model is presented in which the features of the genetically obese (Zucker) fatty rat are compared with those of animals with hypothalamic obesity.
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PMID:The Zucker-fatty rat: a review. 32 51

Excessive food intake and obesity was induced in one member of parabiotic pairs by electrical stimulation (three 30-min sessions/day for 2 wk) of the lateral hypothalamus (LH). The nonstimulated partners reduced spontaneous food intake the fatter the stimulated animals became. This reduced food intake resulted in a decreased body weight, fat content, and fat-free solid body mass. The decrease of food intake was not due to changed social behavior of the obese partner. It must be attributed to transmission of a humoral satiety factor. The very first stimulation of the LH in the stimulated partners resulted in a large increase in blood glucose and glucagon level without much change in the insulin level. These changes in blood parameters were probably due to strong sympathetic arousal. In the nonstimulated animals there were practically no changes in these parameters. One week of fattening resulted in increased basal glucose and insulin levels in the stimulated animals and decreased glucose levels in the nonstimulated partners, in which the basal insulin levels remained nearly normal. Basal glucagon levels were the same in both partners and did not differ from the prefattening situation. At that time during stimulation the obese animals showed a large increase in glucose and glucagon levels and a decrease in insulin level. On the other hand the nonstimulated animals showed a slow gradual increase in glucose and insulin level due to transmission from their fat partners because of the large gradient in these substances between the animals. These phenomena were still more pronounced after 2 wk of fattening. It is tentatively concluded that the humoral satiety factor is neither circulating insulin nor glucagon nor one of the major circulating nutrients.
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PMID:Involvement of a humoral factor in regulation of body weight in parabiotic rats. 32 94

The authors examined 48 patients with different endocrine pathology (relatives of patients with diabetes mellitus with a normal glucose tolerance test, patients with diabetes mellitus, obesity, thyrotoxicosis, and hypothyroidism) and a group of healthy persons. Blood glucagon concentration was determined radioimmunologically on fasting stomach and against the background of insulin hypoglycemia. A marked reduction of glucagon on fasting stomach was noted in patients with diabetes mellitus, and a reduction of the hormone concentration 30 and 60 min after the insulin injection. In obese patients and relatives of diabetic patients the initial blood glucagon level was not different from that in healthy persons. At the same time there was a significant reduction, and in relatives of diabetes patients also a retardation of glucagon secretion against the background of insulin hypoglycemia. The pattern of glucagon secretion in thyrotoxicosis and hypothyroidism proved to be changed.
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PMID:[Glucagon secretion in several endocrine diseases]. 36 65

Obesity in the Zucker rat is accompanied by hyperlipemia, hyperinsulinism, insulin resistance, pancreatic hyperplasia, and islet hypertrophy. This study correlates the morphologic heterogeneity of isolated pancreatic islets with secretion of insulin and glucagon in the perifusion system. Islet size was arbitrarily defined as large (greater than 0.45 mm) or small (smaller than 0.12 mm). Protein content and volume (V = 4/3pir3) were calculated for groups and individual islets, respectively. Islets from obese rats secreted more insulin in response to glucose and aminophylline than islets from lean rats (peak 7.8 +/- 2.4 vs. 1.5 +/- 0.37 microU/islet/min, P less than 0.005). Insulin release was related directly to islet size and protein content. Small islets from lean and obese animals produced less insulin per islet than large islets (P less than 0.005). In terms of islet volume, however, large islets were inefficient insulin releasers as compared to small islets (P less than 0.005). Stimulation with Br-cAMP released glucagon from islets of lean but not from large islets of obese animals (peak 11 +/- 3.3 vs. 4.1 +/- 0.3 pg/microgram protein per minute, P less than 0.05). Arginine produced the same effect on glucagon release (P less than 0.05) as stimulation with Br-cAMP. The observed increased insulin release rates and the blunted glucagon response are related to islet size in the pancreas of the Zucker rat.
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PMID:Correlation between morphology and function in isolated islets of the Zucker rat. 37 79

The effect of age and adiposity on fasting plasma levels of pancreatic polypeptide (HPP), glucagon (IRG), insulin (IRI) and glucose was examined in 263 healthy subjects between the ages of 20-69 yr. Mean plasma levels of hPP rose continuously from the third through the seventh decades. Mean plasma levels of IRG rose within the third and fourth decades but failed to rise further thereafter. Mean plasma levels of IRI did not change with age. Mean plasma levels of glucose rose by approximately 2 mg/dl . decade. The correlations of age with hPP, IRG, glucose, and adiposity were 0.47, 0.35, 0.25 (all P less than 0.01) and 0.15 (P less than 0.05), respectively. When adjustments were made for adiposity, the correlations of age with hPP, IRG, and glucose remained. Adiposity correlated with IRI, IRG, and glucose but when age correction was made, only the correlation of adiposity with IRI persisted. We conclude that: 1) age has a significant effect on fasting plasma levels of hPP and IRG; 2) the patterns of the age-related changes in hPP and IRG are not the same, suggesting that there are differences in the mechanism(s) by which age influences plasma levels of these two pancreatic hormones; and 3) age should be considered in the interpretation of fasting plasma levels of hPP and IRG.
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PMID:Effect of age on fasting plasma levels of pancreatic hormones in man. 40 Jul 40

The metabolic and hormonal changes during a standard physical exercise were studied in healthy subjects and in insulin-dependent diabetics well matched for body weight, and therefore submitted to a similar work load in a physiologic range, and in obese subjects that, owing to their weight, faced a significant heavier work in the same environmental conditions. Moderate work load did not lead to significant changes in metabolic and hormonal blood parameters (blood glucose, FFA and glycerol; insulin, glucagon, growth hormone and cortisol) in healthy subjects. A similar substrate homeostatis was seen in insulin-dependent diabetics, that however showed marked hormonal alterations. In these subjects, indeed, higher levels of plasma glucagon and GH were reached during work and in the recovery phase. Obese subjects, submitted to a heavier work load, presented a marked increase in blood glucose and glycerol which agrees with high GH and cortisol levels, and a subsequent increment of IRI which corresponds to a normalization of blood glucose and glycerol. Obese subjects, therefore, show a normal sensitivity to work load. Considerations about the work load in everyday life are discussed.
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PMID:Metabolic and hormonal changes during exercise in healthy, diabetic and obese subjects. 45 17


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