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

In an attempt to determine whether the decreased number of insulin's receptors in obesity is a result of downregulation of the receptors, diazoxide (5 mg/kg/d) was given to 10 obese subjects. Insulin's suppression by diazoxide in these 10 subjects resulted in a mild glucose intolerance and an increase in insulin's receptors in seven of the 10 subjects. The subjects could be divided into three groups by analyzing the Scatchard plots of their insulin receptor studies before and after diazoxide. Four subjects exhibited an increase in both high affinity and low affinity receptors, three showed an increase only in high affinity receptors, and three failed to demonstrate any change in receptors in response to diazoxide. These studies support the concept that the decreased number of insulin's receptors observed in obesity is a result of the downregulation of the receptors and is not the primary, underlying cause of insulin resistance in obesity, although a contributory role cannot be ruled out.
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PMID:Downregulation of insulin receptors in obese man. 43 66

The acute effect of bilateral electrolytic ventromedial hypothalamic lesions (20-25-m Coulomb stainless steel electrodes) on plasma levels of insulin and glucose was studied in anesthetized rats to determine early effects that would occur before hyperphagia and obesity. In rats fed ad libitum, lesions in the ventromedial hypothalamus (VMH) but not in the cortex produced a marked increase in circulating insulin levels (starting at 20 min postlesion) and a small increase in glycemia which, however, was not significant and could therefore not be the cause of increased insulin secretion. Hyperinsulinemia after VMH lesions was more pronounced when glucose was infused iv at a rate of 7-8 mg/kg . min. Bilateral subdiaphragmatic vagotomy, performed 50 min after VMH lesions, immediately and completely reversed the observed hyperinsulinemia. With the exception of a tendency of lesions producing the highest degree of hyperinsulinemia to be slightly larger than the lesions not producing any hyperinsulinemia, no statement about the critical involvement of a specific hypothalamic locus can be made. It is concluded that electrolytic VMH destruction causes immediate hypersecretion of the pancreatic B cell, an effect that requires the integrity of the vagus nerves. Further localization of the central circuitry responsible for this mechanism, however, will require more specific methods than electrolytic lesions.
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PMID:Acute hyperinsulinemia and its reversal by vagotomy after lesions of the ventromedial hypothalamus in anesthetized rats. 44 4

The characteristics of the glucose and insulin responses during the glucose tolerance test (GTT) in obese people as a group have not been established. We analyzed glucose and insulin levels during GTT in 160 healthy obese patients who averaged 42% over ideal body weight. Statistical upper limit of normal for 2-h glucose was 260 mg/dl in women and 206 mg/dl in men. Although there was a significant correlation between insulin and glucose levels in both sexes and between insulin and degree of obesity in women, r values were relatively low (r less than 0.4 for all). High insulin levels and delayed peak insulin were present in the majority of patients with normal GTT and absent in many of the most obese patients. Results indicate that upper limits of normal glucose for GTT in the obese are much higher than currently accepted criteria.
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PMID:Glucose-insulin response to oral glucose in a healthy obese population. 44 5

The pattern of insulin response to oral glucose over a wide range of glucose tolerance has been studied in two separate ethnic groups--Polynesians and Micronesians. Fasting insulin concentrations were relatively unchanged over the entire range of glucose tolerance in both populations, irrespective of whether comparable lean or obese samples of both groups were studied. The patterns of 2-h plasma insulins were similar over the whole range of glucose tolerance in Polynesians and Micronesians. However, in the comparisons of all subjects, or lean or obese groups of these populations, the plasma insulin concentrations of the Micronesians were both consistently and significantly higher. As the data analysis was arranged to take into account groups with identical 2-h plasma glucose concentrations and comparable degrees of obesity, the differences cannot be attributed to differences in the glucose levels or in obesity. In the presence of similar fasting insulin concentrations, these findings imply an ethnic variability in the pancreatic beta-cell response to oral glucose.
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PMID:Ethnic variability in the plasma insulin response to oral glucose in Polynesian and Micronesian subjects. 44 19

Twenty-seven women with varying degrees of obesity were physically trained for 6 mo on an ad lib. diet. Body fat changes were positively correlated with the number of fat cells in adipose tissue. Obese women with fewer fat cells decreased in weight during training whereas women with severe obesity and an increased number of fat cells even gained weight. Blood pressure decreased consistently after training. Blood pressure elevation was not associated with body fat mass, nor was a decrease in blood pressure associated with a decrease in body fat or with pretraining blood pressure level. There were, instead, correlations between decreases in blood pressure on the one hand and initial concentrations and decreases in plasma insulin and triglycerides and blood glucose on the other. These results suggest an association between elevated blood pressure and metabolic variables. The possibility of treating and preventing early essential hypertension with methods that also correct the metabolic derangement, such as diet and exercise, should be given high priority in further research.
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PMID:Effects of long-term physical training on body fat, metabolism, and blood pressure in obesity. 44 4

Restudy of 306 "new immigrant Yemenite" Jews, an ethnic group in which, upon their arrival in Israel, no diabetes was detected, revealed, 25 yr after their immigration, an increased incidence of diabetes and higher plasma and lipoprotein-lipid levels. The prevalence of diabetes (defined as "glucose intolerance") rose to 11.8% (13.2% males and 9.7% females). Obesity in females resulted in increased prevalence of diabetes in all age groups, while in males it affected the older age group only. The male/female diabetic ratio was affected by weight status--in the underweight, diabetes was more prevalent in males, in the overweight, the rate of diabetes in females equaled that of males. In nondiabetics (those with normal glucose tolerance), neither the glucose tolerance nor the insulin response deteriorated with aging. Most diabetics had a delayed insulin response. However, about 50% of nondiabetics and diabetics had insulin response peak at 60 min and similar insulin levels. It appears that in newly discovered adult-onset diabetics in this population there is no shortage of insulin, but rather shortage of insulin action. In nondiabetics, the levels of plasma cholesterol and triglycerides (TG) were higher than levels upon their arrival. In diabetics, the plasma TG, cholesterol, and LDL-cholesterol levels were higher when compared to those of nondiabetics, especially in the group of overweight males. Hyperlipoproteinemia was diagnosed in 27.7% of diabetics and 11.0% of nondiabetics. In diabetics, the HDL/LDL cholesterol ratio was found to be reduced, significantly so in overweight diabetics.
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PMID:Diabetes, blood lipids, lipoproteins, and change of environment: restudy of the "new immigrant Yemenites" in Israel. 44 7

A study was made of 20 patients with "resistant" obesity selected from a series of about 4000 observed between 1970 and 1976 in an assessment of the possible existence of features distinguishing such patients from those who respond to treatment and display a satisfactory decrease in weight. The group was marked by a higher incidence of familial obesity, earlier onset of overweight, and certain personality features (evaluated by psychometric tests). Their blood sugar and insulin curves, blood cholesterol and uric acid, adipose tissue cellularity, and blood pressure (LHAP) were similar to those in the general series. Whereas their blood triglyceride values were normal, however, those in the general series were up by 21%. It is therefore felt that the clinical tests used at present do not enable the "resistant" obese subject to be distinguished. "Resistant" obesity may well constitute a distinct nosological entity, but one that is only identifiable via the patient's response to treatment.
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PMID:["Resistent" obesity. Clinical and metabolic aspects, cellularity of the adipose tissue and personality factors]. 45 Feb 94

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

The authors have estimated a correlation between the total insulin areas after glucose loading and total somatotropin areas during insulin-induced hypoglycaemia in 30 patients with obesity, as well as in a selected group of 16 patients with simple (essential) obesity. A significant negative correlation was found in both investigated groups. A new hypothesis assuming hyposecretion of somatotropin in obese subjects as a result of hyperinsulinaemia and subsequent increased somatomedin generation is suggested.
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PMID:Relationship between insulin and somatotropin in obesity. 46 74

Aspects of adipose tissue cellularity were examined in 15 non-diabetic premenopausal African women with simple obesity living in Johannesburg. A smaller group of six non-obese Black women served as controls. Adipose tissue was obtained by biopsy from the deltoid, gluteal, and abdominal regions, and the mean fat cell size for each site was determined. Fasting plasma glucose, insulin, and lipid levels, and the glucose and insulin responses to a 100 g oral glucose load, in these subjects provided metabolic data for correlative analyses. As expected, the overall mean and regional adipocyte sizes were significantly larger in the overweight subjects. Significant regional variations in fat cell size were also seen, the gluteal region adipocytes being larger than those of other sites in both obese and non-obese women. A significant positive correlation was found between fat cell size and the percentage of ideal body weight. There was no significant relationship between adipocyte size, however, and any of the metabolic variables measured--notably basal or stimulated plasma insulin. Nearly half of the overweight women showed large adipocytes with normal plasma insulin concentrations. A proportion of African women with hypertrophic obesity do not appear to demonstrate any classical metabolic features of insulin resistance; this may be related partly to their high carbohydrate intake and unusual degree of physical activity. Our results do not, however, indicate that hyperinsulinaemia is completely absent in obese Black women.
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PMID:Adipose cell size in obese Africans: evidence against the existence of insulin resistance in some patients. 46 4


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