Abstract
LPI is chemically characterized by diaminoaciduria, especially lysinuria, and hyperammonemia after amino nitrogen intake. The hyperammonemia is preventable by arginine or ornithine. The plasma concentration of diaminoacids was decreased to 20-50% of the normal mean, presumably because of defective tubular and intestinal absorption. We have suggested that a similar defect in the uptake of diaminoacids by hepatocytes results in hepatic ornithine deficiency. This incapacitates the urea cycle, as urea is formed on the ornithine molecule. We have studied the transport of the nonmetabolized diaminoacid analoque homoarginine into liver slices of 2 patients and 3 controls. The patients had 2 apparent transport systems. One of these, the “low concentration system”, differed clearly from that of the controls. At large substrate concentrations the kinetic constants were similar in both groups of subjects. These findings are in accordance with our hypothesis.
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Simell, O., Perheentupa, J. Transport of homoarginine into liver slices of patients with lysinuric protein intolerance (LPI). Pediatr Res 8, 904 (1974). https://doi.org/10.1203/00006450-197411000-00053
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DOI: https://doi.org/10.1203/00006450-197411000-00053