Interaction between Drug Acetylation and Ethanol, Acetate, Pyruvate, Citrate, and L(minus;)Carnitine in Isolated Rat Liver Parenchymal Cells

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Abstract
The actylation of sulfanilamide and procainamide in suspensions of isolated rat parenchymal cells was studied in the absence and presence of ethanol (33 mM), acetate (0.5-5 mM), citrate (4 mM), pyruvate (4 mM) and L-(-)carnitine (2 mM). Ethanol treatment enhanced the sulfanilamide acetylation; the acetylation of procainamide was unchanged. Acetyl (1-5 mM), citrate and pyruvate treatment enhanced the acetylation of both sulfanilamide and procainamide. Acetate (4 mM) increased both Km and Vmax of both sulfanilamide and procainamide acetylation. Combined treatment with L(-)carnitine and either acetate, pyruvate or citrate enhanced the acetylation rate of sulfanilamide more than acetate, pyruvate or citrate, respectively, alone. In cell suspensions treated with L(-)carnitine and acetate or pyruvate, the acetylation kinetics of sulfanilamide changed from zero-to apparent 1st-order. With procainamide as test drug, a further increase of the acetylation rate was found when L(-)carnitine was added to citrate or pyruvate. Acetyl-CoA increased the rate of sulfanilamide aceytlation in rat liver homogenates in a dose dependent manner.