THE BURNING OF CO TO CO2 BY ISOLATED TISSUES AS SHOWN BY THE USE OF RADIOACTIVE CARBON

Abstract

Various tissues of the frog were exposed to 80% CO and 20% O2 for periods ranging from 5 to 10 hrs. The rates of gas consumption in CO-O2 mixture and in air were measured in a respirometer. The radioactive isotope C14 was used in the CO-O2 mixtures and the amt. of CO burned to CO2 was calculated from radioactivity measurements of the respired CO2. The amt. of CO burned was found to agree with the excess gas consumption in the respirometer, thereby showing that the excess gas consumption was due to the burning of CO to CO2- The rate of CO oxidized by frog tissue was found to be the highest for heart muscle, next for skeletal muscle, and negligible in nerve or skin. The amt. of CO burned to CO2 but retained within the tissue was found to be a small fraction of the total CO burned. It appears that the burning is superimposed on the resting metabolism of muscle tissue with perhaps slight inhibition of the latter. Sodium azide and hydroxylamine completely blocked the oxidation of CO measured by both respirometer and isotope techniques. These findings confirm and extend earlier expts. which utilized less direct methods.