The oxygen consumption of rat tissues in the presence of nitrogen, helium or hydrogen

Abstract

The oxygen consumption rates of Holtzman rat diaphragm, and of slices of liver, brain cortex and kidney cortex were determined for two hours in the presence of 0.21 atm O 2 and 0.79 atm N 2, He or H 2 using the standard Warburg method. The oxygen consumption of rat diaphragms was also studied at increased pressures of He-O 2 or N 2-O 2 and at decreased pressures of O 2 using a pressure microrespirometer. With the exception of young rat liver slices in the first hour and diaphragms in the second hour, there were no significant differences observed in the rates of oxygen consumption of the tissues in the presence of N 2, He or H 2. The oxygen consumption rates of diaphragm were not significantly different in one atm of air or 1 5 atm O 2, and the addition of 3.8 atm N 2 at the same P o 2 did not change the rate. At a Po 2 of 1 atm the oxygen consumption rate was not significantly different in the presence or absence of 4 atm N 2 or He. The observation that small changes in P o 2 in the range from 0.204 to 0.262 atm may produce significant changes in the oxygen consumption rates of the tissues studied has been discussed in relation to interpretation of the results of others. It is concluded that the presence of N 2, He or H 2 does not consistently or significantly affect the rate of oxygen consumption of the four rat tissues studied.