CYSTEINE SUPPLEMENTATION INCREASES GLUTATHIONE, BUT NOT POLYAMINE, CONCENTRATIONS OF THE SMALL-INTESTINE AND COLON OF PARENTERALLY FED NEWBORN RABBITS

The glutathione precursor cysteine is not contained in most total pare nteral nutrition (TPN) formulations, and premature infants may not be capable of synthesizing cysteine because of a deficiency of cystathion ase. Glutathione depletion may have negative effects on host defense a gainst oxidative damage. Several studies have suggested that glutathio ne depletion induces ornithine decarboxylase activity and increases in polyamine concentrations. Since an inverse relationship between polya mine and glutathione concentrations has been suggested, the concentrat ions of both of these compounds may be altered in premature infants re ceiving TPN. We measured glutathione and polyamine concentrations of t he small intestine and colon of prematurely delivered newborn rabbits administered TPN for 7 days after birth with or without added cysteine (75 or 150 mg kg(-1) day(-1)). Maternally reared kits were also studi ed. Total glutathione concentrations in the gastrointestinal tract wer e significantly lower in kits administered cysteine-free TPN than in k its receiving cysteine or who were maternally reared. Polyamine concen trations did not differ among groups. Glutathione depletion of the sma ll intestine and colon does occur during cysteine-free parenteral nutr ition and may compromise intestinal defense against oxidant damage.