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Hyperinsulinemia, or hyperinsulinaemia is a condition in which there are excess levels of insulin circulating in the blood relative to the level of glucose. While it is often mistaken for diabetes or hyperglycaemia, hyperinsulinemia can result from a variety of metabolic diseases and conditions. While hyperinsulinemia is often seen in people with early stage type 2 diabetes mellitus, it is not the cause of the condition and is only one symptom of the disease. Type 1 diabetes only occurs when pancreatic beta-cell function is impaired. Hyperinsulinemia can be seen in a variety of conditions including diabetes mellitus type 2, in neonates and in drug induced hyperinsulinemia. It can also occur in congenital hyperinsulism, including nesidioblastosis. Hyperinsulinemia is associated with hypertension, obesity, dyslipidemia, and glucose intolerance. These conditions are collectively known as Metabolic syndrome. This close association between hyperinsulinemia and conditions of metabolic syndrome suggest related or common mechanisms of pathogenicity.〔 Hyperinsulinemia has been shown to "play a role in obese hypertension by increasing renal sodium retention".〔 In type 2 diabetes, the cells of the body become resistant to the effects of insulin as the receptors which bind to the hormone become less sensitive to insulin concentrations resulting in hyperinsulinemia and disturbances in insulin release.〔Shanik, M.H., Yuping, X., Skrha, J., Danker, R., Zick, Y., and Roth, J. (2008) (Insulin Resistance and Hyperinsulinemia ) “Diabetes Care”, 31(2):s262-s268. Doi 10.2337/dco8-s264〕 With a reduced response to insulin, the beta cells of the pancreas secrete increasing amounts of insulin in response to the continued high blood glucose levels resulting in hyperinsulinemia. In insulin resistant tissues, a threshold concentration of insulin is reached causing the cells to uptake glucose and therefore decreases blood glucose levels. Studies have shown that the high levels of insulin resulting from insulin resistance might enhance insulin resistance.〔 Studies on mice with genetically reduced circulating insulin suggest that hyperinsulinemia plays a causal role in high fat diet-induced obesity. In this study, mice with reduced insulin levels expended more energy and had fat cells that were reprogrammed to burn some energy as heat. Hyperinsulinemia in neonates can be the result of a variety of environmental and genetic factors. If the mother of the infant is a diabetic, and does not properly control her blood glucose levels, the hyperglycemic maternal blood can create a hyperglycemic environment in the fetus. To compensate for the increased blood glucose levels, fetal pancreatic beta cells can undergo hyperplasia. The rapid division of beta cells results in increased levels of insulin being secreted to compensate for the high blood glucose levels. Following birth, the hyperglycemic maternal blood is no longer accessible to the neonate resulting in a rapid drop in the newborn’s blood glucose levels. As insulin levels are still elevated this results in hyperinsulinemia. To treat the condition, high concentration doses of glucose are given to the neonate as required maintaining normal blood glucose levels. The hyperinsulinemia condition subsides after one to two days.〔Ferry, R.J. (2010). (Hyperinsulinism ) “Medscape”.〕 ==Causes== Since hyperinsulinemia and obesity are so closely linked it is hard to determine whether hyperinsulinemia causes obesity or obesity causes hyperinsulinemia, or both. Obese people have an excess of adipose tissue. Adipose tissue is known to secrete various metabolites, hormones and cytokines that may play a role in causing hyperinsulinemia. Specifically cytokines secreted by adipose tissue directly effect the insulin signalling cascade, and thus insulin secretion. Adiponectins are cytokines that are inversely related to percent body fat; that is people with a low body fat will have higher concentrations of adiponectins where as people with high body fat will have lower concentrations of adiponectins. Weyer "et al,." (2011) reported that hyperinsulinemia is strongly associated with low adiponectin concentrations in obese people, though whether low adiponectin has a causal role in hyperinsulinemia remains to be established〔 * Neoplasm, pancreatic cancer, PCOS, Trans Fats〔(), Dieting and exercise〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hyperinsulinemia」の詳細全文を読む スポンサード リンク
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