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Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853
The uptake and metabolism of L-2-oxo-[35S]thiazolidine-4-carboxylate (OTC) was compared with that of L-[35S]cysteine and L-[35S]methionine in studies with freshly isolated rat hepatocytes, renal cortical tubules and enterocytes. All three 35S-labeled substrates were metabolized to glutathione, inorganic sulfur and taurine by hepatocytes and to inorganic sulfur by renal tubules and enterocytes. The rate of metabolite production from OTC was always <30% of that from cysteine or methionine. The transport rate for uptake of [35S]OTC by hepatocytes was less than that observed for uptake of [35S]cysteine or [35S]methionine. The capacity of rat hepatocytes, renal cortical tubules and enterocytes to take up and metabolize OTC is substantially lower than that for uptake and metabolism of cysteine or its normal intracellular precursor, methionine.
KEY WORDS: cysteine methionine rats L-2-oxothiazolidine-4-carboxylate glutathione
1 This material is based upon work supported by the Cooperative State Research Service, U.S. Department of Agriculture under Agreement No. GAM900895 and by New York State Hatch Project 399-472.
2 To whom correspondence should be sent.
Manuscript received 7 December 1990. Revision accepted 12 March 1991.