Ten men with idiopathic
oligospermia were treated with delta 1-testolactone (
Teslac), a potent inhibitor of conversion of
androgens to
estrogens.
Teslac therapy caused a fall in serum
estradiol and
estrone levels of 34% (P less than 0.01) and 41% (P less than 0.01), respectively, and a rise in serum
testosterone and
androstenedione of 47% (P less than 0.02) and 70% (P less than 0.01), respectively. The
testosterone-
estradiol ratio increased by 126% (23.5 +/- 2.5 x 10(-1) to 45.2 +/- 5.0 x 10(-1); P less than 0.01) and the
androstenedione:
estrone ratio increased 231% (4.7 +/- 0.6 x 10(-1) to 12.9 +/- 2.0 x 10(-1); P less than 0.01). Basal and LRH-stimulated serum
gonadotropin levels were unaffected by these changes. Sperm density rose from 10.8 +/- 2.5 to 19.8 +/- 4.7 x 10(6)/ml (P less than 0.01) and total sperm count from 26.8 +/- 6.5 to 60.6 +/- 14.3 x 10(6) (P less than 0.001). There was no significant change in motility or semen volume. Three of the wives became pregnant. There were no adverse effects of
Teslac administration. These data suggest that
Teslac may be an effective treatment for men with idiopathic
oligospermia. Though the data do not clearly elucidate the mechanism of this effect, they are consistent with the possibility that
Teslac's lowering of
estrogen levels may have been responsible for the improvement in spermatogenesis. The findings also suggest that moderate increases in the circulating
androgen-
estrogen ratio do not affect
gonadotropin output in men.