Abstract: Triptolide was given orally to adult male Sprague-Dawley rat sat a dosage of 75 μg/kg for 35 days. After 28 days of treatment, the result of mating tests showed that all the drug treated rats were infertile. At the end of drug treatment, the density of caudal spermatozoa and the weight of cpididymis were reduced significantly. All the spermatozoa were immobile.There was no detectable damage of spermatogenesis and epididymal epithelia in triptolide treated rats under microscopical examination. However, modcrate and severe damage of spermatozoa were seen in the corpus and caudal epididymis. The content of cytosolic and nuclear dihydrotestosterone (DHT) receptors in the caput and caudal epididymides was increased but insignificantly as compared with that of the controls. However, the content of DHT receptor in the cytosal of the ventral prostate was elevated very, significantly (P<0.01). This result suggests that one of the sitcs of action of triptolide might be the epididymis.

Key words: Triptolide, Rat, Reproductive endocrinology, DHT receptors