Effect of Insulin on Glucose Uptake by Mouse Diaphragm Tissue

Abstract

A bioassay method for insulin was developed which measured its stimulating effect on glucose uptake of isolated pooled mouse hemi-diaphragms. A linear log dose-response was obtained between 30 and 3000 micro-units of insulin/ml. The basal glucose uptake as measured in a modified Krebs-Ringer-bicarbonate medium (1 mg glucose/ml) was 2 1/2-4 times that of rat diaphragm tissue. The basal glucose uptake was significantly lowered by increasing concentrations of K and Mg in the medium. Lowering the bicarbonate concentration below 25 m[image] sharply reduced the uptake. An inverse linear relationship between uptake and diaphragm size was noted. The mouse diaphragm method was found to be more sensitive and reliable than the rat diaphragm method.