SHORT-TERM CHANGES IN URINARY GROWTH-HORMONE EXCRETION AND LOWER LEG LENGTH IN HEALTHY-CHILDREN

To investigate any association between changes in lower leg length (LL L) and urinary growth hormone (uGH) excretion, 4 prepubertal children supplied daily 12-hour overnight urine samples and had daily knemometr y performed for 4 weeks. The mean daily and weekly LLL velocity (LLLV) of the group was 0.08 mm/day (95% CI 0.01-0.18) and 0.52 mm/week (ran ge 0.38-0.78), respectively. The mean uGH excretion was 8.9 ng/l (CI 3 .7-13.3), and the mean intrasubject coefficient of variation of uGH wa s 55% (range 32-93). The tallest subject who also had the highest LLLV excreted the least amount of uGH (mean 3.7 ng/l, CI 2.9-4.5). No temp oral relationship was evident between daily uGH excretion and LLL chan ges. There was no evidence of any association between amount of uGH ex creted and LLLV. There remains some doubt on the usefulness of uGH mea surement as the sole predictor of normal GH production.