NEW YORK (Reuters Health) – Most male infertility resulting from a low serum testosterone-to-estradiol ratio can be successfully treated with the selective aromatase inhibitor, anastrozole, researchers report in the February issue of The Journal of Urology.
Dr. Jay D. Raman, from the Weill Medical College of Cornell University, and Dr. Peter N. Schlegel, from the Center for Biomedical Research, both in New York, treated 140 subfertile men who had an abnormal serum testosterone-to-estradiol ratio. The men were given testolactone 100 mg to 200 mg daily, or anastrozole 1 mg daily.
During treatment, the research team monitored changes in testosterone, testosterone-to-estradiol ratio, and semen parameters. In evaluating treatment results, they also took into account obesity, the presence of Klinefelter syndrome, varicocele, or a history of varicocele repair.
During a mean of 6 months of testolactone therapy, testosterone-to-estradiol ratio increased (p < 0.001). Improvement was seen in men with Klinefelter syndrome, varicocele or a history of varicocele repair. Among 12 oligospermic men who had their semen analyzed before and during therapy, sperm concentration increased (p < 0.01), as did motility (p < 0.05) and morphology (p = 0.05). Motility index also increased (p < 0.05), the researchers found.
For men receiving anastrozole for a mean of 4.7 months, serum testosterone-to-estradiol ratio also increased (p < 0.001). However, serum testosterone-to-estradiol ratio did not improve in men with Klinefelter syndrome. Sperm analysis of 25 oligospermic men showed that semen volume increased (p < 0.05) as did sperm concentration (p < 0.001), and motility index (p < 0.005), Drs. Raman and Schlegel found.
Although neither treatment produced significant differences in serum testosterone levels, anastrozole therapy did result in a statistically greater improvement in serum estradiol levels and testosterone-to-estradiol ratios (p < 0.001), the investigators note.
Drs. Raman and Schlegel conclude that "anastrazole is at least equally efficacious as earlier aromatase inhibitors and testolactone in its effect on testosterone, estradiol, testosterone-to-estradiol ratios, and semen parameters in men with low testosterone-to-estradiol levels and infertility. Only patients with the Klinefelter syndrome had better hormonal responses with oral testolactone therapy."