Publication Abstract

Mechanistic effects of a triazinepesticide on reproductive endocrine function in mature male salmon parr

A. Moore and C.P. Waring

The s-triazinepesticide atrazine, a known contaminant of ground and surface water, had a significantsublethal impact upon the pheromonal mediated endocrine system in mature male Atlanticsalmon (Salmo salar L.) parr. Previous studies have demonstrated that ovulatedfemale salmon release a priming pheromone in their urine (considered to be an F-typeprostaglandin) which is subsequently detected by the olfactory system of mature malesalmon and results in increased levels of plasma sex steroids and expressible milt.Short-term exposure of the olfactory epithelium of male parr to concentrations of thepesticide ranging from 2.0-20 µg L-1significantly reduced the olfactory response toprostaglandin F2a. In addition, exposure of male parr to atrazine significantly reducedtheir ability to respond to the priming effect of ovulated female salmon urine. Thepriming effect on milt and plasma 17,20b-dihydroxy-4-pregnen-3-one levels were reduced atwater atrazine concentrations at and above 0.04 µg L-1. The priming effect of urine onplasma testosterone and 11-ketotestosterone concentrations was also affected at pesticideconcentrations at and above 3.6 and 6.0 µg L-1, respectively. Atrazine also affected theaccumulation of steroids in bile and directly impacted upon the testes, modifying17,20b-dihydroxy-4- pregnen-3-one and androgen secretion. The results of the study arediscussed in relation to the possible sublethal impacts of atrazine on the biology ofAtlantic salmon with particular emphasis on olfaction and reproduction.

Reference:

A. Moore and C.P. Waring, 1998. Mechanistic effects of a triazine pesticide onreproductive endocrine function in mature male salmon parr. Pesticide Biochemistry andPhysiology, 62: 41-50.