Excretion of radioactive carbon dioxide by rats after administration of isotopic bicarbonate, acetate, and succinate.

The rate of excretion of C1402 has been followed after the intraperitoneal injection into rats of (1) isotopic bicarbonate, NaHC1403, (2) isotopic acetate, CH3C1400Na, and (3) isotopic succinate, Na00CCH&HzC1400Na. The data so obtained yield information on the rate at which CO2 participates in the metabolic processes of the body, as well as the rate at which isotopic carbon is eliminated following its administration in the three chemical forms. Previous measurements of excretion of isotopic CO, reported in the literature have been few and, in these few, the experiments were not designed to determine the rates of COz excretion following the administration of a single dose of isotopic material (l-3). In the present experiments, the excretion of C1402 and total COz has been measured at frequent intervals up to 4 hours.