LH-RH testing in men with Down's syndrome.

Males with Down's syndrome frequently present incomplete sexual development and are presumed to be sterile. The intent of this study is to clarify the aetiology of diminished sexual function in men with trisomy 21. Single dose LH-RH stimulation tests were performed in 6 men with Down's syndrome. Compared to a control group of 6 mentally retarded, institutionalized males, the subjects with Down's syndrome had markedly elevated basal FSH and slightly elevated basal LH concentrations. The FSH response to LH-RH stimulation was notably increased in the Down's syndrome group, while the LH response showed a lesser increase. Testosterone concentrations were found to be comparable in the two groups. The results are consistent with the clinical assumption that males with Down's syndrome have decreased spermatogenesis and infertility and that their Leydig cell function is less affected.