PARENT SESSION
5C Ecological relevance of endocrine disruption
9:00 AM to 7:00 PM, Tuesday, 08 May 2001
Session Chair:

(T/FF219) Tributyltin disrupts the gonadal steroidogenic enzymes in fish.

McAllister, Brian¹, Kime, David¹, ¹

ABSTRACT- Although it is now well known that tributyltin (TBT) induces imposex in marine gastropods through a mechanism involving inhibition of the aromatase enzyme that converts testosterone into estradiol, little is known about whether similar inhibition of steroidogenesis occurs in teleost fish. We have shown that in the rainbow trout, ppb concentrations of TBT inhibit ovarian aromatase which in fish is essential for vitellogenesis, pituitary-hypothalamic function and sexual differentiation. Furthermore TBT also inhibits the in vitro conversion by sperm of 17-hydroxyprogesterone to the maturation inducing steroid 17,20-dihydroxy-4-pregnen-3-one (17.20P). The data show that environmentally realistic concentrations of TBT may inhibit multiple gonadal steroidogenic enzymes in fish and cause impaired reproductive function.

Key words: tributyltin, fish, steroidogenesis, enzymes