Establishment of testis in vitro assay system for risk assessment of endocrine disrupters

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In order to collect the fundamental information on spermatogenic cells, we made the stage map of seminiferous epithelium in the greater Japanese shrew mole and examined the lectin-histochemical characteristics of their testicular cells. At the same time, we observed the distribution of Smad in hamster testes. As a result, Smad2 and Smad3 mRNA were detected in spermatogonia and spermatocytes. Next, we examined the effect of estrogen on rat testes. After administration of estrogen to 10 week old rats, testosterone decreased to a great degree and testicuiar steroidogenic enzymes also decreased to a degree. Bisphenol-A (BPA), one of endocrine disrupters, was added to the primary Sertoli cell cultre established from 10 day old rat testes at the concentration of 10, 100, lOOOpg/m. At 2 days after treatment, the increase of degenerative Sertoli cells was 7.2, 14.7 and 20.8%, respectively. At 4 days, the increase was 11.4, 19.5 and 28.3%., and at 6 days, the increase was 12.6, 21.3 and 34.9%, respectively. These increases were significant compared with the control. While, BPA was added to the primary Sertoli cell culture established from 1 〜 2 month old goat testes at the concentration of 1,10, lOOum, and the samples was observed at 1,3,5 days after treatment. As a result, similar to the case in rats, the degenerative Sertoli cells increased dose-dependently and time-dependently. Thus, it is possible to postulate that BPA may affect Sertoli cells directly. Then, BPA and 17b estradiol (E2) was added to the organ culture of mouse undifferentiated gonads at the concentration of 0.1, 1, lOum. At 5 days after treatment, the samples were observed. In this case, no obvious changes were detected. In males, normal testicular cord formatin was clearly recognized. Therefore, it is suggested that BPA and E2 do not affect the initial differentiation of gonads directly.