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.

Androgens Decrease Plasma Adiponectin, an Insulin-Sensitizing Adipocyte-Derived Protein

Abstract: Adiponectin, an adipose-specific secretory protein, exhibits antidiabetic and antiatherogenic properties. In the present study, we examined the effects of sex hormones on the regulation of adiponectin production. Plasma adiponectin concentrations were significantly lower in 442 men (age, 52.6 ± 11.9 years [mean ± SD]) than in 137 women (53.2 ± 12.0 years) but not different between pre- and postmenopausal women. In mice, ovariectomy did not alter plasma adiponectin levels. In contrast, high levels of plasma adiponectin were found in castrated mice. Testosterone treatment reduced plasma adiponectin concentration in both sham-operated and castrated mice. In 3T3-L1 adipocytes, testosterone reduced adiponectin secretion into the culture media, using pulse-chase study. Castration-induced increase in plasma adiponectin was associated with a significant improvement of insulin sensitivity. Our results indicate that androgens decrease plasma adiponectin and that androgen-induced hypoadiponectinemia may be related to the high risks of insulin resistance and atherosclerosis in men.

Insulin expression in human thymus is modulated by INS VNTR alleles at the IDDM2 locus

Abstract: Type 1 diabetes or insulin-dependent diabetes mellitus (IDDM) is due to autoimmune destruction of pancreatic beta-cells. Genetic susceptibility to IDDM is encoded by several loci, one of which (IDDM2) maps to a variable number of tandem repeats (VNTR) minisatellite, upstream of the insulin gene (INS). The short class I VNTR alleles (26-63 repeats) predispose to IDDM, while class III alleles (140-210 repeats) have a dominant protective effect. We have reported that, in human adult and fetal pancreas in vivo, class III alleles are associated with marginally lower INS mRNA levels than class I, suggesting transcriptional effects of the VNTR. These may be related to type 1 diabetes pathogenesis, as insulin is the only known beta-cell specific IDDM autoantigen. In search of a more plausible mechanism for the dominant effect of class III alleles, we analysed expression of insulin in human fetal thymus, a critical site for tolerance induction to self proteins. Insulin was detected in all thymus tissues examined and class III VNTR alleles were associated with 2- to 3-fold higher INS mRNA levels than class I. We therefore propose higher levels of thymic INS expression, facilitating immune tolerance induction, as a mechanism for the dominant protective effect of class III alleles.

Insulin: The Structure in the Crystal and its Reflection in Chemistry and Biology by

Abstract: Publisher Summary This chapter reviews the physical, chemical, and biological properties of insulin in the light of the atomic arrangement found in insulin crystals. It also describes the relation of the three-dimensional arrangement of the atoms in the molecule of 2-zinc insulin crystal to the solution properties of insulin (particularly its states of aggregation), to the chemical reaction and chemical modification of the molecule, and to its primary biological activity. Normally the insulin crystals contain two zinc ions to every six molecules of insulin—a hexamer. The slow solution of the crystals provides a method of delaying the action of insulin that closely parallels the methods adopted in the pancreas itself for the storage and release of insulin. Within many β granules, grains can be seen that almost certainly contain zinc insulin hexamers packed in a crystalline array, and in experimental animals diabetes has been induced by chelating agents, such as EDTA, perhaps simply by interfering with normal insulin storage. It, therefore, seems plausible that ready crystallization of insulin in the presence of zinc is a reflection of the storage processes in the β cell.

Diabetes management system and method for controlling blood glucose

Abstract: A diabetes management system for predicting a future blood glucose value of a patient and for recommending a corrective action to the patient when the future blood glucose value lies outside of a target range. The system includes a patient-operated apparatus for measuring blood glucose values and for storing data relating to insulin doses administered to the patient. The apparatus predicts the patient's future blood glucose value based upon the patient's current blood glucose value, the fraction of insulin action remaining from the insulin doses, and the patient's insulin sensitivity. The apparatus also determines the corrective action for the patient when the predicted blood glucose value lies outside of a target range. The system also includes a physician computer in communication with the apparatus for receiving the blood glucose values and insulin dose data and for calculating an adjusted insulin sensitivity for use in subsequent predictions.

The insulin-related ovarian regulatory system in health and disease.

Abstract: I. Introduction II. Insulin and Insulin Receptor A. Structures of insulin and insulin receptor B. Presence of insulin and insulin receptor in the ovary C. Insulin action and the ovary D. Summary III. IGFs and Their Receptors A. IGF peptides and receptors B. Expression of IGFs and IGF receptors in the ovary C. Role of IGFs in ovulatory function and steroidogenesis D. Summary IV. IGF-Binding Proteins (IGFBPs) and Proteases A. Structural relationships among IGFBPs B. IGFBP expression in the ovary C. IGFBP proteases in the ovary D. IGFBP actions in the ovary E. Role of IGFBPs in follicular development and atresia F. Summary V. Polycystic Ovary Syndrome (PCOS) A. Clinical features B. Theories of pathogenesis C. Insulin resistance in PCOS D. Alterations of IGFs and IGFBPs in PCOS E. Summary VI. The Insulin-Related Ovarian Regulatory System: Implications for Therapy A. Treatment of PCOS B. Therapeutic use of IGF-I and IGF-II C. Use of GH in ovulation induction VII. Summary and Conclusions