Long-term effects of glucose on insulin release and glucose oxidation by mouse pancreatic islets maintained in tissue culture.
Rates of glucose oxidation and insulin release in response to a wide range of glucose concentrations were studied in short-term experiments in isolated mouse pancreatic islets maintained in tissue culture for 6 days at either a physiological glucose concentration (6.7mm) or at a high glucose concentration (28mm). The curves relating glucose oxidation or insulin release to the extracellular glucose concentration obtained with islets cultured in 6.7mm-glucose displayed a sigmoid shape similar to that observed for freshly isolated non-cultured islets. By contrast islets that had been cultured in 28mm-glucose showed a linear relationship between the rate of glucose oxidation and the extracellular glucose concentration up to about 8mm-glucose. The maximal oxidative rate was twice that of the non-cultured islets and the glucose concentration associated with the half-maximal rate considerably decreased. In islets cultured at 28mm-glucose there was only a small increase in the insulin release in response to glucose, probably due to a depletion of stored insulin in those B cells that had been cultured in a high-glucose medium. It is concluded that exposure of B cells for 6 days to a glucose concentration comparable with that found in diabetic individuals causes adaptive metabolic alterations rather than degeneration of these cells.
D000818:Animals; D001639:Bicarbonates; D002021:Buffers; D002250:Carbon Radioisotopes; D046508:Culture Techniques; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D051379:Mice; D010084:Oxidation-Reduction
D001639:Bicarbonates; D002021:Buffers; D002250:Carbon Radioisotopes; D007328:Insulin; D005947:Glucose