Exposure of juvenile rainbow trout Oncorhynchus mykiss to methoxychlor results in a dose-dependent decrease in growth and survival but does not alter male sexual differentiation

• Published in: Bulletin of environmental contamination and toxicology Vol. 60; no. 4; pp. 659 - 666
• Main Authors: Krisfalusi, M, Eroschenko, V P, Cloud, J G
• Format: Journal Article
• Language: English
• Published: 01.04.1998
• Subjects: Freshwater; Oncorhynchus mykiss
• ISSN: 0007-4861

The proestrogenic pesticide methoxychlor (MXC) [1,1,1-trichloro-2,2-bis (p-methoxyphenyl) ethane], a substitute for DDT, has been used as a larvicide to control various insect pests. Although MXC is relatively non-toxic to mammals, it has been shown to bioaccumulate and its primary metabolite exhibits estrogenic activity. Since MXC is an environmentally persistent compound with reported estrogenic properties it may have numerous adverse effects on non-target aquatic organisms such as fish. Salmonids may be especially sensitive to the estrogenicity of MXC since gonadal steroids appear to play a critical role in sexual differentiation in these fish. It has been shown that the expected sexual phenotype can be reversed by addition of exogenous androgens or estrogens at the time of gonadal differentiation. Because little attention has been given to the effects of organochlorine pesticides on salmonids, the objective of this study was to determine if chronic MXC exposure effects male juvenile rainbow trout Oncorhynchus mykiss growth, survival or sexual differentiation.