Acetate metabolism: Effects of tracer concentration

A study of the role of tracer acetate concentration in CO 2 − , fatty acid-, and cholesterol-forming systems has been made. By evaluating the specific activity response, i.e., increase, with increasing tracer concentrations, it has been established that the amount of tracer used in in vitro studies may be critical and that this critical concentration may be different for various systems. It appears necessary to determine, for each system using labeled tracers, the amount of the tracer that will trace existing reactions at their normal rate or in situ rate of reaction.