PARENT SESSION
18 - Endocrine Disruption
8:00 AM to 6:30 PM, Monday, 13 May 2002
Exhibition Area

(18-59) Comparative histopathology of zebrafish gonads after disruption of the sex hormone system.

van der Ven, Leo^*,1, Wester, Piet¹, van den Brandhof, Evert-Jan¹, Loendersloot, Hennie¹, Vos, José¹, de Waal, Sandra¹, ¹ RIVM (Dutch National Institute of Public Health and the Environment), Bilthoven, Netherlands

ABSTRACT- Histology may contribute significantly to the understanding of biological effects of hormonal active compounds in in vivo protocols. We conducted short-term (10 days) and long-term (3 weeks for F0 and additional 6 weeks for F1) exposure tests in zebrafish with a panel of compounds covering major interferences with the sex hormone system, i.e. 17-estradiol (E2; estrogen), tamoxifen (anti-estrogen), methyltestosterone (androgen, aromatisable) and 17-methyldihydroxytestosterone (mdhT; androgen, non-aromatisable), and flutamide (anti-androgen). Histological and histomorphometrical analysis of the gonads revealed specific effects of the respective compounds, such as inhibited proliferation of spermatogonia after E2 and accelerated spermatogenic maturation after exposure to mdhT. The presented systematic panel of these effects, shows that histological analysis of the gonads, as employed in this test system, can give clues to the mechanism of action of the respective compounds. In reverse, it can contribute to the identification of the nature of endocrine disrupting effects in undefined field samples.

Key words: sex hormones, gonad histology, zebrafish danio rerio