Effects of Carbon Dioxide Inhalation on Potassium Liberation From the Liver

¹ From the Department of Physiology, University of Rochester School of Medicine and Dentistry, Rochester, New York

Changes in the concentration in the blood plasma of potassium, phosphate, chloride, sodium bicarbonate and glucose were followed in anesthetized cats during the inhalation of different concentrations of CO₂ in oxygen for periods of 30 minutes or more. The typical response consisted of a rapid elevation of K with a return to normal and a slow progressive increase in both glucose and phosphate. The adrenal-sympathico-hepatic system is involved since the response is largely abolished by cervical section of the spinal cord, by adequate doses of adrenergic blocking agents and by simultaneous clamping of the hepatic artery and portal vein, and is usually diminished by adrenalectomy. Estimates were made of the total absolute amounts of K, glucose and P so liberated and the molecular ratios were found to be approximately 4:13:1. This is relatively more K than is usually associated with glycogen storage in the liver. Further analyses in the blood indicated an increase in the density of both blood and plasma due to loss of water. At the same time there is a decrease in the concentration of both Na and Cl in the plasma as well as a decrease in bicarbonate as measured after equilibration with 5% CO₂. This acidosis, due partly to lactic acid, occurs in spite of the fact that the gain in K and loss in Cl exceeds the loss in Na. The response of the liver to high CO₂ has a threshold which is usually between 10 and 20%. At concentrations of CO₂ below this threshold there is a small fall in plasma K which would be expected from the fact that whole blood is better buffered than tissues.