Continuous measurement of 14C-labeled carbon dioxide and lactic acid by cultured cells grown in Leighton tubes.

A procedure for continuous measurement of ¹⁴CO₂ production by cultured cells grown in Leighton tubes has been described. The apparatus developed also permits aliquots of the incubation medium to be taken during the experiments for analysis of labeled metabolites released into the solution. A simple method for determination of [¹⁴C]lactic acid in such aliquots has been described. The reproducibility and usefulness of the apparatus has been demonstrated by incubating fibroblasts with glucose labeled in the C-1 or C-6 position, and examining the effects of selected drugs on CO₂ and lactic acid production.