Urate changes in lean and obese boys during pubertal development.

Uric acid metabolism is not uniform throughout puberty. Serum urate increases progressively in obese boys as puberty advances, but it increases significantly only at the end of puberty in lean subjects. Urate filtered per unit of body weight increases in all subjects at the end of puberty when fractional excretion is diminished. Urate clearance decreases a the beginning of puberty in obese boys and at the end of puberty in lean subjects. Urate excretion corrected for body weight and the urinary uric acid to creatinine ratio do not change over the course of pubertal development in both lean and obese boys. These results suggest the following hypotheses: (1) renal retention of urate may represent the first mechanism by which uricemia is enhanced at puberty; (2) the kidney may finely modulate serum uric acid concentration through different mechanisms of urate handling, presumably occurring at different tubular sites; and (3) obesity may evoke sooner the urate changes that in lean boys are observed at the end of puberty.