URINARY HUMAN GROWTH-HORMONE MEASUREMENT USING A HIGHLY SENSITIVE SANDWICH ENZYME-IMMUNOASSAY - DIAGNOSTIC AND THERAPEUTIC USES IN PATIENTS WITH GROWTH-HORMONE DEFICIENCY

Several reports indicate that urinary hGH excretion is significantly lower in patients with either partial (PGHD) or complete GH deficiency (CGHD) than in normal but short children (NSC) or normal children (NC). However, there is an overlap between the NSC and NC groups and the PGHD group. Using a highly sensitive sandwich enzyme immunoassay, we investigated whether the measurement of urinary hGH can clearly separate the PGHD and CGHD groups from the NSC and NC groups. In addition, we measured the urinary excretion of synthetic methionyl-hGH (met-hGH) in PGHD and CGHD after sc injections of 2 and 4 IU and im injections of 4 IU in an attempt to determine the optimal replacement dose. Total 24–h urinary hGH excretion in each patient examined for 2 consecutive days varied from 1 day to the next. There were no differencies in urinary hGH excretions between the NSC group and the NC group. The lower values for daily urinary hGH excretion in the NSC group overlapped some of the higher values in the PGHD group. However, when the mean urinary hGH level of both days was used, the 24-h urinary hGH excretion clearly separated the PGHD (5.5 ± 2.3 ng/day; range, 1.3–9.2; n = 21) and CGHD (1.9 ± 0.9 ng/day; range, 0.6–3.6; n = 14) groups from the NSC (12.8 ± 3.1 ng/day; range, 9.3–17.5; n = 10) and NC (14.6 ± 3.1 ng/day; range, 10.6–19.0; n = 6) groups without any overlap. A mean urinary hGH value less than 9.0 ng/day during a 2-day collection strongly suggested GH deficiency. Ten of 16 patients with PGHD and CGHD who received 2 IU met-hGH, sc, had urinary hGH levels within the range of the mean ± SD in NSC. These patients received daily sc 0.097 ± 0.024 IU/kg hGH injections. These results suggest that the measurement of 24-h urinary hGH excretion is noninvasive, accurate, and useful for the screening of GH deficiency. The mean value on 2 days of 24-h urinary hGH excretion for the screening of GH deficiency is estimated to be less than 9.0 ng/day. The optimal dose of GH as therapy for GH deficiency is demonstrated as daily sc injection of 0.1 IU/kg hGH, 0.7 IU/kg/week. To convert international units of met-hGH to milligrams, divide by 2.4. © 1990 by The Endocrine Society.