Changes in plasma urate, creatinine, alkaline phosphatase and the 24 hours excretion of hydroxyproline during sexual maturation in adolescents.

The relative concentrations of plasma uric acid and creatinine, the alkaline phosphatase activities and the 24 hour urinary excretion of hydroxyproline together with sexual maturity ratings are reported in a population of normal British schoolchildren studied longitudinally over a three-year period. The children were all of European origin and their ages ranged from 7 to 17 years. Plasma urate rose sharply during puberty in the boys but not in the girls. Plasma creatinine rose in both sexes during maturation. Plasma alkaline phosphatase activity rose to a peak at genital maturity 3(G3) in boys and breast maturity 2(B2) in girls and subsequently fell rapidly in both sexes. The 24-hour urinary secretion of hydroxyproline was high in young boys and rose to a peak during G3 and G4 and then fell rapidly. In girls there was no significant peak in concentrations, although there was a fall during B4 and B5, and levels were higher throughout puberty than those reported for adult females.