IMPROVED INSULIN RECEPTOR ASSAY - EFFECTS OF AN ANTI-DIABETIC SULFONYLUREA ON LIVER MEMBRANE INSULIN RECEPTORS FROM OBESE HYPERGLYCEMIC MICE

A simple assay of liver membrane insulin receptors is described, under conditions which apparently stabilized the insulin‐receptor complex. The receptor population was measured in the presence of physiological doses of radioactive hormone under conditions which minimized negative co‐operativity effects. Equilibrium between receptor and hormone was attained in vitro within 60 min of incubation time at 13°C with no apparent loss of binding sites after 3 h of incubation. Liver membranes from lean mice possessed 8.8 times the receptor number per mg membrane protein measured in membranes from obese hyperglycaemic (ob/ob) littermates. After treatment of ob/ob mice with ARDF‐26 (Gliquidon; Boehringer Ingelheim Ltd) the concentration of liver membrane insulin receptors was increased 5 fold. 1979 British Pharmacological Society