Investigation of the in vivo estrogenicity of the UV-filters 4-methylbenzylidene camphor and octyl methoxy cinnamate in rainbow trout (Oncorhynchus mykiss)

Abstract

The estrogenic activity of the chemical UV-filters, 4-methylbenzylidene camphor (4-MBC) and octyl methoxy cinnamate (OMC) was investigated in an in vivo rainbow trout (Oncorhynchus mykiss) assay. Plasma vitellogenin concentrations were quantified by means of an Enzyme Linked Immuno Sorbent Assay (ELISA) in juvenile rainbow trout before and after intraperitoneal injection of the test compounds. Injection of 4-MBC on day 0, 3, 6 and 10 in the exposure period caused dose and time dependent increases in the concentration of plasma vitellogenin. Significant elevation of vitellogenin concentrations in plasma was demonstrated from 151 mg 4-MBC kg^-1 injection^-1. Logistic regression analysis relating the percentage of responding fish to the injected dose of 4-MBC resulted in ED₁₀, ED₅₀ and ED₉₀ values of 37, 115 and 194 mg kg^-1 injection^-1, respectively, after 14 days of exposure (4 injections). Injections with OMC (up to 202 mg kg^-1 injection^-1) did not result in a statistically significant response in groups of exposed fish, although some individual fish showed elevated concentrations of vitellogenin in plasma. The results confirm that 4-MBC is estrogenic in fish in vivo.

Keywords: 4-MBC; Estrogenic activity; OMC; Rainbow trout; UV-filters; Vitellogenin.