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Autophagy, a stress-induced lysosomal degradative pathway, has been assumed to exert similar metabolic effects in different organs. Here, we establish a model where autophagy plays different roles in insulin-producing β cells versus insulin-responsive cells, utilizing knockin (Becn1) mice manifesting constitutively active autophagy. With a high-fat-diet challenge, the autophagy-hyperactive mice unexpectedly show impaired glucose tolerance, but improved insulin sensitivity, compared to mice with normal autophagy. Autophagy hyperactivation enhances insulin signaling, via suppressing ER stress in insulin-responsive cells, but decreases insulin secretion by selectively sequestrating and degrading insulin granule vesicles in β cells, a process we term "vesicophagy." The reduction in insulin storage, insulin secretion, and glucose tolerance is reversed by transient treatment of autophagy inhibitors. Thus, β cells and insulin-responsive tissues require different autophagy levels for optimal function. To improve insulin sensitivity without hampering secretion, acute or intermittent, rather than chronic, activation of autophagy should be considered in diabetic therapy development.
This article was published in the following journal.
Name: Cell reports
Insulin resistance, defined as attenuated sensitivity responding to insulin, impairs insulin action. Direct causes and molecular mechanisms of insulin resistance have thus far remained elusive. Here w...
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Obesity and latent inflammation in adipose tissue significantly contribute to the development of insulin resistance (IR) and type 2 diabetes. Here we studied whether the antiinflammatory interleukin-4...
Research in animals and first experiments in humans indicate that insulin action in the brain regulates peripheral insulin sensitivity. One major organ might be the liver. Previous studies...
To investigate the effects of different dietary regimens on muscle wasting, insulin/IGF-1 resistance. Further, to explore whether LPD+KA decrease the activation of autophagy associate with...
This study will look into insulin sensitivity (how the body responds to insulin) and effects of meals on type 2 diabetics comparing insulin peglispro to insulin glargine. The study has two...
The objectives of this study are to evaluate the safety and tolerance of 20 mg (10 mg BID) of HE3286 when administered orally over 28 days to obese insulin-resistant adult subjects and, to...
An association between insulin resistance and mitochondrial dysfunction has been observed in aging, T2D, and in offspring of patients with T2D. It remains to be determined whether pharmac...
A syndrome with excessively high INSULIN levels in the BLOOD. It may cause HYPOGLYCEMIA. Etiology of hyperinsulinism varies, including hypersecretion of a beta cell tumor (INSULINOMA); autoantibodies against insulin (INSULIN ANTIBODIES); defective insulin receptor (INSULIN RESISTANCE); or overuse of exogenous insulin or HYPOGLYCEMIC AGENTS.
Diminished effectiveness of INSULIN in lowering blood sugar levels: requiring the use of 200 units or more of insulin per day to prevent HYPERGLYCEMIA or KETOSIS. It can be caused by the presence of INSULIN ANTIBODIES or the abnormalities in insulin receptors (RECEPTOR, INSULIN) on target cell surfaces. It is often associated with OBESITY; DIABETIC KETOACIDOSIS; INFECTION; and certain rare conditions. (from Stedman, 25th ed)
A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).
An insulin preparation that is designed to provide immediate and long term glycemic control in a single dosage. Biphasic insulin typically contains a mixture of REGULAR INSULIN or SHORT-ACTING INSULIN combined with a LONG-ACTING INSULIN.
Insulin formulation containing substance which delays or retards time period of the absorption of insulin.
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