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

To determine whether hyperglycemia in the obese hyperglycemic (ob/ob) mouse is related to enhanced activity of the pancreatic beta cell, streptozotocin (175 mg/kg) was injected into lean and ob/ob mice at 8 wk of age. The influence of this injection upon glucose metabolism, adipose cellularity, pancreatic morphology and immunoreactive insulin (IRI) release from isolated pancreatic islets was measured. The plasma glucose levels before and after an oral glucose load were elevated in lean and decreased in ob/ob mice 2 wk after treatment with streptozotocin. By 5 wk after this treatment, a reduced pancreatic islet size, beta cell number and a decreased pancreatic islet IRI release were present in both lean and ob/ob mice. At this time, plasma glucose was still elevated in lean, but depressed in ob/ob mice and the insulin responsiveness in muscle and adipocytes was unchanged. Hyperglycemia abates in the ob/ob mouse as hypersecretion of insulin is diminished, but these observations may not be directly related, since streptozotocin affects key metabolic activities of the livers as well as the pancreatic beta cell. The progression of obesity and status of adipose cellularity are not directly related to hyper-insulinemia, since they are not altered following streptozotocin treatment.
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PMID:Effects of streptozotocin on glucose metabolism, insulin response, and adiposity in ob/ob mice. 12 52

Primary hypersecretion of insulin has been suggested as one possibility for the genetic fault of ob/ob mice. To test this hypothesis, streptozotocin (SZO) was used to reduce permanently insulin secretion in young lean and obese mice. After establishment of hyperglycaemia and weight reduction in treated obese mice (obese-SZO), daily insulin replacment was begun in some (obese-SZO-Ins). Obese-SZO mice maintained insulin levels and body weights similar to lean controls, though they were shorter and fatter, while food intake and blood sugar levels exceeded lean values. Obese-SZO-Ins mice with reduced islet hyperplasia, but great insulin resistance, gained more weight than obese-SZO mice; had high serum insulin and controlled blood glucose; and exhibited hyperphagia. These results suggest that primary hypersecretion of insulin cannot be the genetic defect, as ob/ob mice are hyperphagic, hyperglycaemic, insulin resistant, and "obese" even when insulin levels are restricted.
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PMID:Effects of long-term restricted insulin production in obese-hyperglycemic (genotype ob/ob) mice. 13 28

Carbohydrate metabolism was studied in eight patients with Down's syndrome, aged 8 to 18 years. Diabetic glucose tolerance was observed in only one patient with obesity. This impaired glucose tolerance was improved with the weight reduction due to diet restriction. The flat glucose tolerance curves with low peak values were also observed in the other two patients. In the remaining five patients, normal glucose tolerance was obtained. Insulin response and free fatty acid levels during oral glucose load were not characteristic except for the diabetic patient with obesity. The sera of Down's syndrome showed normal binding capacity for insulin. These results suggest that obesity might partly participate in the impaired glucose tolerance in Down's syndrome.
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PMID:Carbohydrate metabolism in Down's syndrome. 16 Jun 33

The status of insulin-receptor interactions in a variety of insulin-resistant states is reviewed. Utilizing large adipocytes from adult rats and small fat cells from young rats, we have conducted a series of in vitro experiments in an attempt to determine the cellular alteration(s) responsible for the insulin resistance associated with obesity. Stimulation of glucose oxidation by insulin is reduced in large cells. Studies using a mimicker of insulin action, spermine, as well as measurements of 125I-insulin binding to large and small cells indicate that receptor number and affinity are not responsible for hormone resistance. Furthermore, when rapid and direct measurements of sugar uptake were made, insulin stimulation was virtually identical in both cell types. These findings indicate that large adipocytes have an efficient insulin-responsive D-glucose transport system and suggest that the apparent hormone resistance may be due to alterations in intracellular glucose metabolism. It has been proposed that altered insulin-receptor interaction underlies the insulin resistance of human obesity. We have investigated this particular aspect of insulin action by 125I-insulin binding studies. Similar numbers of insulin receptors per cell and affinity for insulin were observed in adipocytes obtained from normal weight subjects and morbidly obese patients. Thus, the initial step in insulin action is unaltered in human obesity.
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PMID:Relation of insulin receptors to insulin resistance. 16 83

The clinical and biochemical features of eleven patients with Type V hyperlipoproteinaemia have been reviewed. All patients were male, and there was a high incidence in the group of obesity, vascular disease, acute abdominal pain, gout, diabetes mellitus and alcoholism. Plasma cholesterol concentrations ranged from 212 to 1512 mg/100ml and triglycerides from 708 to 7670 mg/100 ml. Lipaemia was associated with significant hyponatraemia, and also interfered with the determination of plasma glucose and serum amylase. Chylomicronaemia and hyperprebetalipoproteinaemia were accompanied by reduction in the pools of beta and alpha lipoproteins. All lipoprotein classes were relatively depleted of cholesterol compared to triglyceride. There was a variable pattern of treatment response. In some patients alcohol withdrawal produced a rapid improvement in plasma lipids. In diabetes mellitus there were two types of response: a rapid one in chronic insulin deficiency, and secondly, a more gradual one in mild diabetes associated with hyperinsulinaemia. In other patients there was a rapid response to carbohydrate-calorie restriction but the respective contributions of each of the steps remained unclear.
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PMID:Type V hyperlipoproteinaemia re-visted: findings in a sydney population. 16 79

Insulin receptor concentrations in liver plasma membranes of New Zealand Obese (NZO) mice have been studied. When NZO mice were implanted with normal islets of Langerhans their blood glucose and plasma insulin declined. When the implanted islets were removed these changes were reversed and the mice reverted to their insulin resistant state. Changes were observed in the binding of 125I-insulin to liver plasma membranes of implanted NZO mice. Binding increased when the plasma insulin was decreased and conversely insulin binding decreased when the plasma insulin levels became elevated. The increased insulin binding was not accompanied by any changes in the affinity of NZO liver receptors for insulin.
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PMID:The control of insulin receptors in the New Zealand obese mouse. 17 9

Obesity in obese-hyperglycaemic mouse is associated with an increase in number and size of adipocytes. Adipocytes from the obese mouse showed increased incorporation of [14C]acetate and[14C]glucose into triacylglycerol. This increased capacity of triacylglycerol formation was correlated with increased activities of various triacylglycerol-forming enzymes measured in the microsomal fraction of adipose tissue from obese mice. Microsomal fractions from lean and obese mice contained sn-glycerol 3-phosphate acyltransferase, phosphatidate phosphohydrolase and diacylglycerol acyltransferase. Phosphatidate phosphohydrolase was also detected in the soluble fraction. In the presence of Mg2+, the phosphatidate phsophohydrolase from the soluble and the microsomal fractions was active towards membrane-bound phosphatidate. Among the three enzymes studied here, the increase in Mg2+-dependent phosphatidate phosphohydrolase was most prominent in adipose tissue of obese mice.
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PMID:Triacylglycerol biosynthesis in the adipose tissue of the obese-hyperglycaemic mouse. 18 34

To determine if an effective method existed for distinguishing the physiologic hypoglycemia of fasting from pathologic hypoglycemia, 72-hour fasts were conducted in 60 women and 20 men of normal weight, in 16 obese subjects, and in six of 11 patient with insulinomas. Only the pattern of change of the immunoreactive-insulin-to-glucose ratio (the I/G ratio), calculated at major time intervals of the fast, provided a clear-cut distinction between these groups; plasma glucose values alone could not make this distinction. The mean fasting I/G ratio was calculated for each subject from that subject's I/G ratios at 12-hour intervals during the fasting period. In no single case did the mean I/G ratio during fasting for an individual of normal weight equal or exceed the control I/G. I/G ratios increased dramatically during fasting in each patient with an insulinomas. Normal obese patients (15% greater than ideal body weight) did not provide a diagnostic problem, since, regardless of sex, glucose values of less than 55 mg/dl. did not occur. Although the pattern of change of the I/G ratio was extremely useful, the basal I/G ratio alone was potentially misleading; this was due to overlap of basal I/G ratios between subjects with simple obesity and patients with insulinomas. In addition, absolute values for the I/G ratio varied with the technique employed for measuring glucose and insulin. Change of the I/G ratio, however, was independent of the techniques used for measuring glucose and insulin. DIABETES 26:161-65, March, 1977.
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PMID:Hypoglycemia in man pathologic and physiologic variants. 19 73

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


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