Stereoselectivity in glutathione conjugation and amidase-catalyzed hydrolysis of the 2-bromoisovalerylurea enantiomers in the single-pass perfused rat liver.

Stereoselective glutathione conjugation and amidase-catalyzed hydrolysis of [(R)- and (S)-]2-bromoisovalerylurea (BIU), yielding bromoisovaleric acid (BI) and urea, have been observed in the rat in vivo and in isolated rat hepatocytes. The metabolism of enantiomeric (R)- and (S)-BIU was presently examined in the single-pass perfused rat liver with varying input concentrations (8-250 microM). Steady-state hepatic extraction ratios for (R)-BIU (0.

Estimations of intestinal and liver first-pass metabolism in vivo. Studies on gentisamide conjugation in the rat.

In this paper a method is introduced to study both intestinal and liver metabolism in the intact rat by cannulation of the jugular vein, carotid artery, pyloric vein (into the portal vein), and bladder. In this preparation, the rat received an initial dose followed by iv (I) and then intraportal (II) infusions. Gentisamide (2,5-dihydroxybenzamide, GAM) was used since it forms monosulfate (GAM-2S and GAM-5S) and monoglucuronide (GAM-5G) conjugates, metabolites that are not further metabolized.

Improved receptor assay for measuring digoxin activity.

We describe a receptor assay of digoxin activity involving Na+/K+-ATPase (EC 3.6.1.