Metabolism of Carbaryl by Kidney, Liver, and Lung from Human Postembryonic Fetal Autopsy Tissue

Abstract

Metabolic profiles of carbaryl in human postembryonic fetal autopsy tissue were determined using an in vitro tissue-maintenance technique. 1-Naphthyl-¹⁴C or N-methyl-¹⁴ C-carbaryl was applied to growth medium containing explants of the tissue. Each mixture was incubated for 18 hr and the medium analyzed by DEAE-cellulose column chromatography. Fetal liver performed the metabolic processes of demethylation, hydrolysis, hydroxylation, and oxidation, followed by conjugation, as was found with adult liver. However, the anionics from fetal liver amounts to 20% of those found with adult liver. The kidney made naphthyl glucuronide and naphthyl sulfate, whereas the lung produced naphthyl sulfate from carbaryl. The metabolic activities of the fetal kidney and lung were close to the corresponding human adult tissues based upon the anionic metabolites found and the amount of unmetabolized carabryl in the medium after 18 hr of incubation. Silica gel chromatography of ether-extractable neutral fractions from DEAE-cellulose revealed 3,4, and 9 ether-extractable metabolites from lung, kidney, and liver, respectively. The present study shows that the in vitro technique is capable of semiquantitatively demonstrating the metabolic activities of specific organs from the human fetus.