Abstract
A recently developed batch microcalorimeter was used for studying heat production in beta-cell-rich pancreatic islets isolated from obese-hyperglycemic mice. In the absence of glucose, the rate of heat production was 50 nW/islet increasing to 90 nW/islet when the islets were exposed to 20 mM glucose. The data obtained are consistent with an increase in the caloric value of oxygen with glucose concentration, as might be expected when the beta-cells utilize proportionally more carbohydrate as a source of energy.