Use of a five-compartment closed model to describe the effects of ethanol inhalation on the transport and elimination of injected pyruvate in the rat.

A five-compartment closed model was established using the system of differential equations. The completely analytical solution of a five-compartment closed model was found using the Laplace transform. 2-[14C]Pyruvate kinetics were studied in rats without and with inhalation of vaporized ethanol, and were modelled by the five-compartment closed model, i.e. injected site, blood, eliminated 14CO2 in air, eliminated 14C in urine and faeces. The kinetic parameters were estimated using the analytical solution of the five-compartment closed model to fit eliminated 14CO2, and 14C in urine and faeces simultaneously. The compartmental analysis showed that the inhalation of vaporized ethanol can increase 2-[14C]pyruvate trans-membrane, trans-tissue processes and oxidation rate. The model developed is useful for general pharmacokinetic and toxicokinetic analysis as well as for studies on ethanol.