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.

Insulin receptors are widely distributed in the central nervous system of the rat.

Abstract: WHILE insulin can affect the function of the central nervous system (CNS) by producing hypoglycaemia, there is substantial evidence suggesting that insulin can also act directly on cells of the CNS to modify their function1–4. In a study of the phylogeny of the insulin receptor, Posner5 reported specific binding of 125I-insulin to membrane preparations from whole brain of rat, monkey and pigeon. Specific receptors for insulin have been detected in the hypothalamus of monkeys but not in the cerebral cortex or thalamus6; other regions of the CNS were not studied. We report here the presence of substantial concentrations of insulin receptors in discrete regions of the CNS of the rat. We detected specific binding of insulin in every area studied, although it differed by as much as five- to 10-fold among regions. The insulin receptor of the cerebral cortex was most extensively characterised, and by all criteria it was indistinguishable from the insulin receptor on classical target tissues (liver, muscle and fat) as well as other cells of humans, rodents7–10, and other mammals and non-mammalian vertebrates.

The influence of glucose-lowering therapies on cancer risk in type 2 diabetes

Abstract: Aims/hypothesis The risk of developing a range of solid tumours is increased in type 2 diabetes, and may be influenced by glucose-lowering therapies. We examined the risk of development of solid tumours in relation to treatment with oral agents, human insulin and insulin analogues. Methods This was a retrospective cohort study of people treated in UK general practices. Those included in the analysis developed diabetes >40 years of age, and started treatment with oral agents or insulin after 2000. A total of 62,809 patients were divided into four groups according to whether they received monotherapy with metformin or sulfonylurea, combined therapy (metformin plus sulfonylurea), or insulin. Insulin users were grouped according to treatment with insulin glargine, long-acting human insulin, biphasic analogue and human biphasic insulin. The outcome measures were progression to any solid tumour, or cancer of the breast, colon, pancreas or prostate. Confounding factors were accounted for using Cox proportional hazards models. Results Metformin monotherapy carried the lowest risk of cancer. In comparison, the adjusted HR was 1.08 (95% CI 0.96–1.21) for metformin plus sulfonylurea, 1.36 (95% CI 1.19–1.54) for sulfonylurea monotherapy, and 1.42 (95% CI 1.27–1.60) for insulin-based regimens. Adding metformin to insulin reduced progression to cancer (HR 0.54, 95% CI 0.43–0.66). Theriskforthoseonbasalhumaninsulin alone vs insulin glargine alone was 1.24 (95% CI 0.90–1.70). Compared with metformin, insulin therapy increased the risk of colorectal (HR 1.69, 95% CI 1.23–2.33) or pancreatic cancer(HR 4.63,95% CI2.64–8.10),but did not influencethe riskofbreastorprostatecancer.Sulfonylureaswereassociated with a similar pattern of risk as insulin. Conclusions/interpretation Those on insulin or insulin secretagogues were more likely to develop solid cancers than those on metformin, and combination with metformin abolished most of this excess risk. Metformin use was associated with lower risk of cancer of the colon or pancreas, but did not affect the risk of breast or prostate cancer. Use of insulin analogues was not associated with increased cancer risk as compared with human insulin.

The role for endoplasmic reticulum stress in diabetes mellitus.

Abstract: Accumulating evidence suggests that endoplasmic reticulum (ER) stress plays a role in the pathogenesis of diabetes, contributing to pancreatic beta-cell loss and insulin resistance. Components of the unfolded protein response (UPR) play a dual role in beta-cells, acting as beneficial regulators under physiological conditions or as triggers of beta-cell dysfunction and apoptosis under situations of chronic stress. Novel findings suggest that "what makes a beta-cell a beta-cell", i.e., its enormous capacity to synthesize and secrete insulin, is also its Achilles heel, rendering it vulnerable to chronic high glucose and fatty acid exposure, agents that contribute to beta-cell failure in type 2 diabetes. In this review, we address the transition from physiology to pathology, namely how and why the physiological UPR evolves to a proapoptotic ER stress response and which defenses are triggered by beta-cells against these challenges. ER stress may also link obesity and insulin resistance in type 2 diabetes. High fat feeding and obesity induce ER stress in liver, which suppresses insulin signaling via c-Jun N-terminal kinase activation. In vitro data suggest that ER stress may also contribute to cytokine-induced beta-cell death. Thus, the cytokines IL-1beta and interferon-gamma, putative mediators of beta-cell loss in type 1 diabetes, induce severe ER stress through, respectively, NO-mediated depletion of ER calcium and inhibition of ER chaperones, thus hampering beta-cell defenses and amplifying the proapoptotic pathways. A better understanding of the pathways regulating ER stress in beta-cells may be instrumental for the design of novel therapies to prevent beta-cell loss in diabetes.

Mean amplitude of glycemic excursions, a measure of diabetic instability.

Abstract: Three normal, three stable diabetic, and eight unstable diabetic subjects were investigated, with continuous automated blood glucose analysis for forty-eight-hour periods, during metabolic balance studies of six days9 duration under near normal conditions (fed and ambulatory) after the attainment of clinically optimal diabetic regulation. The studies on unstable diabetics were performed during constant dietary intake, with one or two daily injections of intermediate-acting insulin and then repeated with four daily injections of short-acting insulin. A characteristic of blood glucose behavior, the mean amplitude of glycemic excursion (MAGE), was measured. MAGE was small for normals (range, 22 to 60 mg./100 ml.), larger for stable diabetics (67 to 82 mg./100 ml.), and largest for unstable diabetics (119 to 200 mg./100 ml.). Associated with a significant decrease ( p = 0.004) in the mean diurnal glycemic level (from 146 to 244 mg,/100 ml. to 101 to 152 mg./100 ml.) achieved through the use of four daily doses of short-acting insulin there was a significant increase ( p = 0.006) in hypoglycemic episodes (from 0 to 4/48 hr. to 3 to 6/48 hr.) without significant change in MAGE. The persistently large value of MAGE despite therapy with multiple injections of short-acting insulin appears to be a characteristic of unstable diabetes.