Effect of Insulin on the Potassium and Inorganic Phosphate Content of the Medium in Experiments with Isolated Rat Diaphragms

Abstract

Diaphragms were removed from 10 rats of 80-100 g. body wt. and cut in half; 10 hemidiaphragms were incubated in 20 ml. of buffer soln. with 200 mg.% of glucose and mineral composition closely resembling blood serum, and equilibrated with 93% O2 and 7% CO2, giving a final pH of 7.4. The other 10 hemidiaphragms were incubated in 20 ml. of a similar soln. to which 0.5 units of insulin/ml. had been added. Both samples were kept at 37[degree]C and shaken continuously; samples of the media were removed after 30, 45, 60, 90, 120, and 150 min., and analyzed for inorganic phosphate, K, and glucose. Glucose utilization was increased by insulin, and there was a drop in the K level during the first hour, followed by a rise which was probably associated with autolysis. In all samples K level was lower in the insulin-containing medium than in the control. The inorganic phosphate concn. rose steadily in both flasks, and no significant difference was noted in this respect between the two.