PROTEIN SYNTHESIS AND INSULIN RELEASE IN MICRODISSECTED ISLETS OF STEROID DIABETIC MICE

1975 ◽  
Vol 80 (1_Suppla) ◽  
pp. S39
Author(s):  
K.-G. Petersen ◽  
B. Kröncke
Keyword(s):  
Protein Synthesis ◽  
Insulin Release ◽  
Diabetic Mice

Role of insulin and IGF-I in activation of muscle protein synthesis after oral feeding

1996 ◽  
Vol 270 (4) ◽  
pp. E614-E620 ◽  
Author(s):  
E. Svanberg ◽  
H. Zachrisson ◽  
C. Ohlsson ◽  
B. M. Iresjo ◽  
K. G. Lundholm
Keyword(s):  
Protein Synthesis ◽  
Skeletal Muscles ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Oral Feeding ◽  
Myofibrillar Proteins ◽  
Diabetic Mice ◽  
Igf I ◽  
Stimulation Of

The aim was to evaluate the role of insulin and insulin-like growth factor I (IGF-I) in activation of muscle protein synthesis after oral feeding. Synthesis rate of globular and myofibrillar proteins in muscle tissue was quantified by a flooding dose of radioactive phenylalanine. Muscle tissue expression of IGF-I mRNA was measured. Normal (C57 Bl) and diabetic mice (type I and type II) were subjected to an overnight fast (18 h) with subsequent refeeding procedures for 3 h with either oral chow intake or provision of insulin, IGF-I, glucose, and amino acids. Anti-insulin and anti-IGF-I were provided intraperitoneally before oral refeeding in some experiments. An overnight fast reduced synthesis of both globular (38 +/- 3%) and myofibrillar proteins (54 +/- 3%) in skeletal muscles, which was reversed by oral refeeding. Muscle protein synthesis, after starvation/ refeeding, was proportional and similar to changes in skeletal muscle IGF-I mRNA expression. Diabetic mice responded quantitatively similarly to starvation/refeeding in muscle protein synthesis compared with normal mice (C57 Bl). Both anti-insulin and anti-IGF-I attenuated significantly the stimulation of muscle protein synthesis in response to oral feeding, whereas exogenous provision of either insulin or IGF-I to overnight-starved and freely fed mice did not clearly stimulate protein synthesis in skeletal muscles. Our results support the suggestion that insulin and IGF-I either induce or facilitate the protein synthesis machinery in skeletal muscles rather than exerting a true stimulation of the biosynthetic process during feeding.

Role of Ca2+ in impaired insulin release from islets of diabetic (C57BL/KsJ-db/db) mice

1980 ◽  
Vol 239 (2) ◽  
pp. E132-E138
Author(s):  
E. G. Siegel ◽  
C. B. Wollheim ◽  
G. W. Sharp ◽  
L. Herberg ◽  
A. E. Renold
Keyword(s):  
Tissue Culture ◽  
Beta Cell ◽  
Insulin Release ◽  
Glucose Concentration ◽  
Insulin Response ◽  
Isolated Islets ◽  
Diabetic Mice ◽  
Impaired Insulin ◽  
Insulin Response To Glucose

The involvement of Ca2+ in the impaired insulin release of diabetic C57BL/KsJ-db/db mice was studied. Twenty-week-old severely hyperglycemic mice were compared to nondiabetic C57BL/KsJ mice as controls. Collagenase-isolated islets were maintained for 46 h in tissue culture allowing for equilibration at the same glucose concentration (8.3) mM). The insulin content of both types of islets was similar. In control islets preloaded during culture with 45Ca2+ glucose-induced insulin release was associated with increased 45Ca2+ effux. Islets from diabetic mice showed markedly reduced insulin response to glucose and a smaller increase in 45Ca2+ efflux. Because insulin release was strikingly potentiated by 3-isobutyl-1-methylxanthine (IBMX), even more than in control islets, there was no generalized release defect. In both types of islets, IBMX potentiation was accompanied by a further enhanced 45Ca2+ efflux, possibly suggesting that cAMP effects are associated with increased cytosol Ca2+% concentrations. As Ca2+ uptake was stimulated by glucose in both types of islets, a defect may lie in the mechanism by which glucose uses cellulr calcium to raise cytosol Ca2+ in the beta-cell of these diabetic mice.

scholarly journals Effects of hypoglycemic components in ginseng radix on blood insulin level in alloxan diabetic mice and on insulin release from perfused rat pancreas.

1981 ◽  
Vol 4 (6) ◽  
pp. 410-417 ◽  
Author(s):  
MASAYASU KIMURA ◽  
ISAMI WAKI ◽  
TADASHI CHUJO ◽  
TAKEO KIKUCHI ◽  
CHIZUKO HIYAMA ◽  
...  
Keyword(s):  
Insulin Release ◽  
Insulin Level ◽  
Diabetic Mice ◽  
Perfused Rat Pancreas ◽  
Rat Pancreas ◽  
Blood Insulin

scholarly journals The inhibition of glucose-stimulated insulin secretion by primary amines. A role for transglutaminase in the secretory mechanism

1984 ◽  
Vol 219 (3) ◽  
pp. 819-827 ◽  
Author(s):  
P J Bungay ◽  
J M Potter ◽  
M Griffin
Keyword(s):  
Protein Synthesis ◽  
Insulin Secretion ◽  
Insulin Release ◽  
Glucose Oxidation ◽  
Glucose Utilization ◽  
Potent Inhibitor ◽  
Primary Amines ◽  
Cross Linking ◽  
Maximal Velocity ◽  
Glucose Stimulated Insulin Secretion

Rat pancreatic islets contain a Ca2+-activated and thiol-dependent transglutaminase (EC 2.3.2.13) comparable in activity with that found in rat liver, lung and spleen. The Ca2+-dependence of this enzyme is such that half-maximal velocity was obtained in the region of 40 microM. Preincubation of rat islets with primary-amine substrates of transglutaminase (monodansylcadaverine, methylamine, ethylamine, propylamine and cystamine) led to an inhibition of glucose-stimulated insulin release by these amines. Kinetic analysis of the competitive substrates methylamine, monodansylcadaverine, propylamine and ethylamine for their ability to inhibit islet transglutaminase activity indicated a potency that matched their ability to inhibit glucose-stimulated insulin release. When these amines were tested for their effects on glucose-stimulated protein synthesis and glucose utilization, the most potent inhibitor of insulin release, monodansylcadaverine, had no effect on either process at 100 microM. The amines cystamine, ethylamine, methylamine and propylamine had variable effects on these metabolic processes. For ethylamine, methylamine and propylamine, concentrations were found which inhibited glucose-stimulated insulin release in a manner which was found to be independent of their effects on either glucose oxidation or protein synthesis. Primary amines may therefore inhibit insulin release through their incorporation by islet transglutaminase into normal cross-linking sites. A role for protein cross-linking in the secretory mechanism is suggested.

scholarly journals Electrogenetic cellular insulin release for real-time glycemic control in type 1 diabetic mice

Science ◽  
2020 ◽  
Vol 368 (6494) ◽  
pp. 993-1001 ◽  
Author(s):  
Krzysztof Krawczyk ◽  
Shuai Xue ◽  
Peter Buchmann ◽  
Ghislaine Charpin-El-Hamri ◽  
Pratik Saxena ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Real Time ◽  
Insulin Release ◽  
Ectopic Expression ◽  
Diabetic Mice ◽  
Real Time Control ◽  
Β Cells ◽  
Time Control ◽  
Stimulation Of

Sophisticated devices for remote-controlled medical interventions require an electrogenetic interface that uses digital electronic input to directly program cellular behavior. We present a cofactor-free bioelectronic interface that directly links wireless-powered electrical stimulation of human cells to either synthetic promoter–driven transgene expression or rapid secretion of constitutively expressed protein therapeutics from vesicular stores. Electrogenetic control was achieved by coupling ectopic expression of the L-type voltage-gated channel CaV1.2 and the inwardly rectifying potassium channel Kir2.1 to the desired output through endogenous calcium signaling. Focusing on type 1 diabetes, we engineered electrosensitive human β cells (Electroβ cells). Wireless electrical stimulation of Electroβ cells inside a custom-built bioelectronic device provided real-time control of vesicular insulin release; insulin levels peaked within 10 minutes. When subcutaneously implanted, this electrotriggered vesicular release system restored normoglycemia in type 1 diabetic mice.

Decreased turnover of soluble liver proteins in mice with alloxan-induced diabetes

1981 ◽  
Vol 241 (2) ◽  
pp. E151-E159 ◽  
Author(s):  
W. E. Duncan ◽  
J. S. Bond
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Protein Turnover ◽  
Diabetic Mice ◽  
Liver Cytosol ◽  
Diabetic State ◽  
Chronic Form

Mice with alloxan-induced diabetes were used as a model to assess whether the synthesis and/or degradation of soluble liver proteins in general is affected in vivo by the diabetic state. Protein turnover was measured 2-3 wk after diabetes was induced. Degradation of liver cytosol proteins was decreased in diabetic mice as measured by the loss of protein radiolabeled with [14C]bicarbonate. The incorporation of radiolabeled amino acids into protein was also decreased in diabetic mice. When [3H]leucine was administered as the precursor for protein synthesis, the radiospecific activity of leucine derived from leucyl-tRNA in livers was similar in control and diabetic mice. Thus, the rate of protein synthesis appears to be decreased. There was no indication that diabetes affected the turnover of long- or short-lived proteins differentially. The activities of several cellular proteinases were unaffected or slightly decreased in livers of diabetic mice. These data indicate that protein turnover is decreased in this chronic form of diabetes.

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