The effect of ammonium ion concentration on the activity of adenylate cyclase in various rat tissues in vitro

The effects of three different ammonium ion concentrations (0.143; 1.43; 14.3 mmol .1(-1)) on adenylate cyclase activities in liver, muscle, fat and brain tissue in vitro were studied in the rat. At physiological levels, ammonium ions reduced adenylate cyclase activity in liver and fat by about 30%, did not affect enzyme activity in muscle tissue but increased adenylate cyclase activity in brain by 40%. Similar effects were observed at higher ammonium ion concentrations though there were no statistically significant correlations between ammonium ion concentration and the degree of change of enzyme activity.