Assessment of seminal estradiol and testosterone levels as predictors of human spermatogenesis.

The proposed hypothesis for this study was that seminal testosterone/estradiol levels and/or their ratios may be a good indicator for predicting normal spermatogenesis. The concentrations of estradiol and testosterone in seminal fluid were measured using competitive immunoassay techniques in specimens collected from 192 infertile patients and 103 normospermic men. Infertile patients were subdivided into three groups according to their semen analysis results and testicular biopsy: oligozoospermia, obstructive azoospermia (OA), and nonobstructive azoospermia (NOA). Results showed that seminal testosterone levels in the infertile groups were lower than in the normospermic individuals (P < .01), whereas seminal estradiol levels in the OA group were significantly higher than those in normospermic and NOA groups (P < .01). Testosterone/estradiol ratios in the seminal plasma from the infertile groups were significantly lower than that in the normospermic group (P < .01). However, seminal estradiol levels among normospermic and NOA groups showed no significant differences. These results suggest that the local balance between androgen and estrogen, or their ratios, may play an important role in maintaining normal spermatogenesis. Also, decreased seminal testosterone/estradiol ratio may be a good indicator for identifying the absence of sperm production in NOA patients.