[Long-term therapy of oligozoospermia with the aromatase inhibitor testolactone]

In a pilot study, 13 subfertile men with idiopathic normogonadotropic oligozoospermia were treated by the aromatase inhibitor testolactone for a period of 6 months. During the administration of 1 g testolactone daily, a significant increase in the sperm count, total sperm output and the absolute number of motile and progressively motile spermatozoa was observed 3 and 6 months after the initiation of therapy, but there were no significant changes in the percentage of motile and progressively motile spermatozoa, sperm morphology or ejaculate volume. The serum hormone levels of testosterone, LH, FSH and oestradiol were assessed before and during testolactone administration; there was a significant increase of testosterone and FSH after 1 and 3 months of treatment, but LH levels increased only during the 1st month of therapy. The oestradiol level showed a significant decrease, while the increase in testosterone/oestradiol ratio was more than twice as expected. The pregnancy rate was 17%. No severe side-effects were reported during testolactone therapy. The results of the study support the hypothesis that oestrogens are involved in the regulation of human spermatogenesis.