Growth and somatomedin responses to growth hormone in Down's syndrome.

Five growth retarded children with Down's syndrome, three girls and two boys aged between 3 1/2 and 6 1/2 years with trisomy 21, were treated with human growth hormone for six months. Before treatment the growth hormone response to sleep and insulin-arginine load, as well as serum concentrations of insulin, thyroid hormones, and cortisol was found to be in the normal range. During the treatment with human growth hormone the growth velocity increased in all the children with Down's syndrome from 2.3-2.8 cm to 3.3-5.8 cm per six months. The serum concentrations of immunoreactive insulin like growth factor 1 (IGF-1) were low before treatment and increased during the treatment with human growth hormone. The serum concentrations of immunoreactive insulin like growth factor 2 (IGF-2), which were within the normal range, however, increased during treatment with human growth hormone. Children with Down's syndrome respond to treatment with human growth hormone, with an increase in both growth velocity and serum somatomedin concentrations.