Diagnostic meaning of the urinary output of Nepsilon-methylated lysines. Investigation of healthy individuals and patients with malignant diseases, myopathies or renal failure

Abstract

In the urine of 36 healthy persons the excretion of the three Nepsilon-methylated lysines and some other basic amino acids was determined. The following average values, related to 1 g creatinine, were found: Lys(Me) 16.2 mumol, Lys(Me2) 31.2 mumol, Lys(Me3) 40.5 mumol. The 24-hour excretion in 6 adults related to 1 kg body weight, had the following average values: Lys(Me) 0.37 mumol, Lys(Me2) 0.88 mumol, Lys(Me3) 0.92 mumol. In patients with degenerative or inflammatory myopathies (6 cases) as well as with generalized tumors (7 cases) urinary output of methyllysines was not significantly altered. In a patient with extremely impaired renal function, it was found that the plasma level and the excretion pattern of the methylated lysines were unequivocally altered. Metabolic stability and renal excretion of 3H-labelled l-Lys(Me3) were investigated in man. During a 24 hour period 65 per cent of Lys(Me3) was excreted into the urine unmetabolized after intravenous injection but not more than 20 per cent after oral administration.