Effect of ammonia on glucose oxidation by isolated rat adipocytes

The effect of ammonium and acetate salts on glucose metabolism in isolated rat adipocytes was studied. Ammonia in low concentration (1-10 mM) was found to inhibit insulin-stimulated CO2 production. Acetate had no effect on this system except at high concentrations (100 mM), at which it stimulated CO2 production. Ammonium and acetate salts had an anti-lipolytic effect at high concentration (100 mM) but no effect on lipolysis at lower concentrations. The observation that trace amounts of salts can affect a biological assay system suggests that other biological assay system may also be altered by contaminating buffer salts from protein isolation steps.