Estimation of Average Times of Residence, Recycle, and Interconversion of Blood-Borne Compounds Using Tracer Methods

Abstract

Average times corresponding to various processes of distribution and metabolism of circulating compounds are denned: mean time of residence during one or all passages of the compound through the vascular system, mean time required for the compound to reenter the circulation after leaving it, and mean time involved in the conversion of 1 blood-borne compound to another. Formulae are derived to calculate these parameters from data obtained in experiments which tracers are injected intravenously and specific activities are measured. Examples of average times for hormones have been computed using published data.