Pituitary and testicular response to hypothalamic LH-releasing hormone (LH-RH) in normal and oligospermic men

A comparative study was done of the basal and post-LH-RH stimulation levels of LH, FSH and Testosterone (T) in 10 healthy, male volunteers, aged 24-35 years, and in 25 normogonadotropic oligospermic men aged 23-43 years in whom other endocrine, urologic and/or vascular diseases had been rules out. Seventeen of the latter group underwent bilateral testicular biopsy. Each subject received rapid i.v. injection of 50 mug synthetic LH-RH at 8:00 A.M. Serum levels of LH, FSH and T were determined by radioimmunoassay on samples obtained immediately before and 30 and 45 minutes after injection. As compared to normals, oligospermic men had a lower average LH response, although the basal values did not differ significantly from normal. FSH levels did not differ significantly between groups, although some individual patients showed higher and some lower than normal values. The possibility of stimulating T secretion with LH-RH was confirmed. Average serum T levels rose more slowly and reached lower levels in the oligospermic men than in normal men. There was no correlation between LH and FSH rises. It is postulated that some patients with normogonadotropic oligospermia may have latent insufficiency of pituitary gonadotropic functional reserve for one or both hormones and/or of the Leydig cell function. The need for individual analysis of results and their correlation with testicular biopsy findings is commented.