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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.


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Journal ArticleDOI
01 Dec 1999-Diabetes
TL;DR: Observations indicate that antioxidant treatment can exert beneficial effects in diabetes, with preservation of in vivo beta- cell function, and provides further support for the implication of oxidative stress in beta-cell dysfunction in diabetes.
Abstract: Oxidative stress is produced under diabetic conditions and possibly causes various forms of tissue damage in patients with diabetes. The aim of this study was to examine the involvement of oxidative stress in the progression of pancreatic beta-cell dysfunction in type 2 diabetes and to evaluate the potential usefulness of antioxidants in the treatment of type 2 diabetes. We used diabetic C57BL/KsJ-db/db mice, in whom antioxidant treatment (N-acetyl-L-cysteine [NAC], vitamins C plus E, or both) was started at 6 weeks of age; its effects were evaluated at 10 and 16 weeks of age. According to an intraperitoneal glucose tolerance test, the treatment with NAC retained glucose-stimulated insulin secretion and moderately decreased blood glucose levels. Vitamins C and E were not effective when used alone but slightly effective when used in combination with NAC. No effect on insulin secretion was observed when the same set of antioxidants was given to nondiabetic control mice. Histologic analyses of the pancreases revealed that the beta-cell mass was significantly larger in the diabetic mice treated with the antioxidants than in the untreated mice. As a possible cause, the antioxidant treatment suppressed apoptosis in beta-cells without changing the rate of beta-cell proliferation, supporting the hypothesis that in chronic hyperglycemia, apoptosis induced by oxidative stress causes reduction of beta-cell mass. The antioxidant treatment also preserved the amounts of insulin content and insulin mRNA, making the extent of insulin degranulation less evident. Furthermore, expression of pancreatic and duodenal homeobox factor-1 (PDX-1), a beta-cell-specific transcription factor, was more clearly visible in the nuclei of islet cells after the antioxidant treatment. In conclusion, our observations indicate that antioxidant treatment can exert beneficial effects in diabetes, with preservation of in vivo beta-cell function. This finding suggests a potential usefulness of antioxidants for treating diabetes and provides further support for the implication of oxidative stress in beta-cell dysfunction in diabetes.

709 citations

Journal ArticleDOI
TL;DR: Systemic administration of FGF-21 reduced plasma glucose and triglycerides to near normal levels in genetically compromised diabetic rodents and led to significant improvements in lipoprotein profiles, including lowering of low-density lipop Protein cholesterol and raising of high-density Lipoprotein cholesterol.
Abstract: Fibroblast growth factor (FGF)-21 has been recently characterized as a potent metabolic regulator. Systemic administration of FGF-21 reduced plasma glucose and triglycerides to near normal levels in genetically compromised diabetic rodents. Importantly, these effects were durable and did not come at the expense of weight gain, hypoglycemia, or mitogenicity. To explore the therapeutic properties of FGF-21 in a nongenetically modified primate species, and thus demonstrate the potential for efficacy in humans, we evaluated its bioactivity in diabetic nonhuman primates. When administered daily for 6 wk to diabetic rhesus monkeys, FGF-21 caused a dramatic decline in fasting plasma glucose, fructosamine, triglycerides, insulin, and glucagon. Of significant importance in regard to safety, hypoglycemia was not observed at any point during the study. FGF-21 administration also led to significant improvements in lipoprotein profiles, including lowering of low-density lipoprotein cholesterol and raising of high-density lipoprotein cholesterol, beneficial changes in the circulating levels of several cardiovascular risk markers/factors, and the induction of a small but significant weight loss. These data support the development of FGF-21 for the treatment of diabetes and other metabolic diseases.

708 citations

Journal ArticleDOI
TL;DR: In this paper, the association between obesity and impaired insulin sensitivity has been recognized, although a subgroup of obese individuals seems to be protected from insulin resistance, while the rest of the population appears to be obese.
Abstract: The association between obesity and impaired insulin sensitivity has long been recognized, although a subgroup of obese individuals seems to be protected from insulin resistance. In this study, we ...

708 citations

Journal ArticleDOI
TL;DR: It is shown that SIRT1 is downregulated in insulin-resistant cells and tissues and that knockdown or inhibition of Sirt1 induces insulin resistance, and that increased expression of SIRT 1 improved insulin sensitivity, especially under insulin- resistant conditions.

708 citations

Journal ArticleDOI
TL;DR: The results indicate that in PCO, a significant degree of insulin resistance exists, which clearly is not related to obesity.
Abstract: To determine whether insulin resistance occurs in polycystic ovarian disease (PCO) in the absence of obesity and acanthosis nigricans, circulating levels of insulin in response to oral glucose administration were measured in 10 nonobese PCO patients without acanthosis nigricans and in 10 normal women matched for weight and height. Mean serum testosterone (T), androstenedione (A), dehydroepiandrosterone (D), D sulfate, and LH levels were significantly elevated in the PCO patients compared to those in control subjects. In PCO patients, the mean +/- SE basal insulin level (18.7 +/- 2.9 microU/ml) and the sum of the insulin levels in response to glucose (674 +/- 119 microU/ml) were significantly greater than those in the control group (11.0 +/- 0.8 microU/ml and 248 +/- 29 microU/ml, respectively). In all subjects, serum levels of T and A, but not D and D sulfate, were significantly correlated to basal insulin levels and insulin sums. Serum cortisol, GH, and PRL levels were similar in both groups. These results indicate that in PCO, a significant degree of insulin resistance exists, which clearly is not related to obesity. The positive correlation of serum T and A levels to circulating insulin levels in this study suggests that the insulin resistance in PCO may be, in part, a consequence of hyperandrogenism.

707 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20243
20232,520
20225,252
20213,164
20203,368
20193,376