Maturation of urinary proteoglycan excretion

Urinary proteoglycan excretion was studied using two newly established methods in subjects aged between 1 and 22 years. Analysis of glycan moieties showed an age-dependent decrease from 9.1±5.5 (SD) g/mol creatinine (n=5) at the age 1–6 years to 1.9±1.3 (n=5,P<0.01) in those aged 16–22 years. Marked qualitative changes in the proteoglycan electrophoretic pattern occurred during the first and second years of life. Two major proteoglycan bands with a molecular weight of 50 kDa decreased in intensity so that the pattern resembled the adult configuration after 6 years of age. The latter consisted of a major band with a molecular weight of 80–100 kDa, the bands corresponding to a molecular weight of 50 kDa and lighter bands of molecular weight around 32 kDa. These changes may be related to functional maturation of the kidney as a whole and to an increase in the number of mature nephrons.