Oral administration of epsilon N-acetyllysine and homocitrulline in lysinuric protein intolerance.

The defect of epithelial diamino acid transport in lysinuric protein intolerance (LPI) results from an abnormality of the basolateral cell membranes. Therefore the lysine deficiency, which is one of the consequences of this defect, cannot be corrected by oral administration of lysine, either in free or peptide form. In search of useful lysine derivatives, we studied in patients with LPI the absorption after oral administration of homocitrulline and epsilon N-acetyllysine. Acetyllysine, but not homocitrulline, normalized the subnormal plasma lysine concentrations.