Short boys treated with growth hormone show normal progression of testicular size and achieve normal serum testosterone concentrations

Objective: To determine whether there is evidence for impaired testicular function at final height in short boys treated with growth hormone (GH) during their childhood and adolescence. Study design: The analysis was restricted to males who had isolated GH deficiency or idiopathic short stature, and who were included in the Swedish National Registry and the Swedish GH trials. The subjects had to have been treated with GH for at least 4 years; the treatment had to have been started prepubertally, given for at least one year before the onset of puberty and the subjects had to have reached final height. One hundred and eleven boys fulfilled the criteria. Methods: Testicular volumes were determined by orchidometer in each boy when GH treatment was started and at final height. Samples for testosterone measurements were collected from 77 boys at final height, and were measured by RIA. Results: Each subject had normal testicular size (15 ml or more) and for those in whom concentrations were determined, serum testosterone levels and diurnal rhythm were normal. Conclusions: The results of our survey do not show evidence of testicular impairment following GH therapy.