[Urinary alanine aminopeptidase excretion in children: reference values and effect of nephrotropic contrast media]

The catalytic activity of alanine aminopeptidase (EC 3.4.11.2) in urine shows a clear cut difference between boys (1530 mU/d X m2) and girls (1143 mU/d X m2). Nineteen children (preterms to 14 years) received contrast media (loxaglate (Hexabrix) (N = 15) or lotalamate (Conray 70) (N = 4] according to the diagnostic indication. The alanine aminopeptidase activity increases to 10-fold of the initial value in the loxaglate and 19-fold of the initial value in the lotalamate group. These results demonstrate a much higher response of the kidney to contrast medium in children than in adults.