Influence of androgens on inositol secretion and sperm transport in the epididymis of rats.

The effects of unilateral efferent duct ligation, bilateral castration or testosterone replacement on the spermatocrit and inositol concentrations in luminal fluid removed by micropuncture from the rat epididymis were investigated. By 5 days after efferent duct ligation, there were substantial falls in the spermatocrit in the caput and corpus, but no change in the cauda. After 7 days there was an increase in the spermatocrit in the cauda. After castration there were more marked reductions in the spermatocrit in the caput and corpus but there was no change in the cauda. The spermatocrit in the corpus, but not in the caput, remained normal when castrated animals were treated with testosterone. The inositol concentrations in luminal fluid from all three sites were not changed after ligation of the efferent ducts but were greatly reduced after castration; this fall was prevented by testosterone treatment. The results support the suggestion that inositol is secreted in the rat epididymis and also indicate that the secretory process is controlled by androgens.