Insulin

About: Insulin is a research topic. Over the lifetime, 124295 publications have been published within this topic receiving 5129734 citations. The topic is also known as: human insulin.

Determination of total serum insulin (IRI) in insulin-treated diabetic patients

Abstract: A routine method is described for the determination of total IRI (imraunoreactive insulin) in insulintreated diabetics. The method involves an easy acid ethanol extraction, whereby antibody-bound IRI is dissociated and separated, together with the “free” IRI from the serum proteins and the antibodies. The recovery of IRI in this procedure is about 80%. After the separation, the isolated total IRI is measured in an immunoassay, using ethanol for the separation of free and antibody bound125I-insulin. In 169 diabetic patients treated with insulin in doses of from 6 to 120 units/day, the fasting serum total IRI was between 6 and 4374 μU/ml, with a mean of 392 μU/ml. During treatment with insulin, the level of total IRI increased from normal values, registered during the first two months, to a higher level which became stable after about 5 months of treatment. The increase in IRI occurred simultaneously with the formation of antibodies. Insulin-resistant patients showed very high IRI levels.

Metabolic Abnormalities and Cardiovascular Disease Risk Factors in Adults with Human Immunodeficiency Virus Infection and Lipodystrophy

Abstract: We evaluated metabolic and clinical features of 71 HIV-infected patients with lipodystrophy by comparing them with 213 healthy control subjects, matched for age and body mass index, from the Framingham Offspring Study. Thirty HIV-infected patients without fat redistribution were compared separately with 90 matched control subjects from the Framingham Offspring Study. Fasting glucose, insulin, and lipid levels; glucose and insulin response to standard oral glucose challenge; and anthropometric measurements were determined. HIV-infected patients with lipodystrophy demonstrated significantly increased waist-to-hip ratios, fasting insulin levels, and diastolic blood pressure compared with controls. Patients with lipodystrophy were more likely to have impaired glucose tolerance, diabetes, hypertriglyceridemia, and reduced levels of high-density lipoprotein (HDL) cholesterol than were controls. With the exception of HDL cholesterol level, these risk factors for cardiovascular disease (CVD) were markedly attenuated in patients without lipodystrophy and were not significantly different in comparison with controls. These data demonstrate a metabolic syndrome characterized by profound insulin resistance and hyperlipidemia. CVD risk factors are markedly elevated in HIV-infected patients with fat redistribution.

Adipose tissue as a buffer for daily lipid flux

Abstract: Insulin resistance occurs in obesity and Type II (non-insulin-dependent) diabetes mellitus, but it is also a prominent feature of lipodystrophy. Adipose tissue could play a crucial part in buffering the flux of fatty acids in the circulation in the postprandial period, analogous to the roles of the liver and skeletal muscle in buffering postprandial glucose fluxes. Adipose tissue provides its buffering action by suppressing the release of non-esterified fatty acids into the circulation and by increasing triacylglycerol clearance. In particular, the pathway of 'fatty acid trapping' (adipocyte uptake of fatty acids liberated from plasma triacylglycerol by lipoprotein lipase) could play a key part in the buffering process. If this buffering action is impaired, then extra-adipose tissues are exposed to excessive fluxes of lipid fuels and could accumulate these in the form of triacylglycerol, leading to insulin resistance. These tissues will include liver, skeletal muscle and the pancreatic beta cell, where the long term effect is to impair insulin secretion. Adipose tissue buffering of lipid fluxes is impaired in obesity through defects in the ability of adipose tissue to respond rapidly to the dynamic situation that occurs after meals. It is also impaired in lipodystrophy because there is not sufficient adipose tissue to provide the necessary buffering capacity. Thus, the phenotype, at least with regard to insulin resistance, is similar with both excess and deficiency of adipose tissue. Furthermore, this concept could provide a framework for understanding the action of the thiazolidinedione insulin-sensitizing agents.

Fish oil prevents insulin resistance induced by high-fat feeding in rats

Abstract: Non-insulin-dependent diabetes mellitus is an increasingly prevalent disease in Western and developing societies. A major metabolic abnormality of non-insulin-dependent diabetes is impaired insulin action (insulin resistance). Diets high in fat from vegetable and nonaquatic animal sources (rich in linoleic acid, an omega-6 fatty acid, and saturated fats) lead to insulin resistance. In rats fed high-fat diets, replacement of only 6 percent of the linoleic omega-6 fatty acids from safflower oil with long-chain polyunsaturated omega-3 fatty acids from fish oil prevented the development of insulin resistance. The effect was most pronounced in the liver and skeletal muscle, which have important roles in glucose supply and demand. The results may be important for therapy or prevention of non-insulin-dependent diabetes mellitus.