Effects of Short-Term Growth Hormone Therapy in Short Children without Growth Hormone Deficiency

ABSTRACT. Evaluation of 24-hour endogenous growth hormone (GH) secretion was carried out in 62 children, aged 7-16 years, who did not have classic GH deficiency (GHD). The mean 24-hour GH concentration, determined at 20-minute intervals over 24 hours, was variable, ranging from 1.28 to 11.39 μg/l with a mean of 4.95 ± 2.55 μl (± SD). There was a positive correlation between mean 24-hour GH concentration and plasma insulin-like growth factor I (IGF-I) values ( r = 0.54; p < 0.01). Recombinant human GH, 0.1 IU/kg/day was administered to 30 of the 62 children for 6 months followed by 6 months'observation without treatment. Thereafter, GH was administered at the same dose for a further 6 months to 16 children. The mean height velocities before, during, and after the first treatment period were 4.3 ± 0.9, 7.3 ± 1.9 and 4.9 ± 2.0 cm/year (mean ± SD), respectively. The height velocity during treatment was greater than pre- and post-treatment values ( p < 0.001). The height velocity Increased again during the second treatment period to a mean of 8.5 ± 2.0 cm/year ( p < 0.001). Nine other children were treated continuously in a similar manner for 1 year and their height velocity increased significantly from 4.1 ± 1.4 to 6.0 ± 1.9 cm/year ( p < 0.001). According to our criteria, 29 of the 39 children (74.4%) who were treated for 6-12 months showed a GH-dependent height increase during therapy. There were no differences between the children who responded to GH treatment and those who did not in terms of Chronological age, bone age, plasma IGF-I level, maximal GH level to insulin-induced hypoglycaemia, or mean 24-hour plasma GH concentration. These data indicate that some short children without GHD respond to GH treatment with an increased height velocity. Further investigations are required to determine the effect of GH on final height.