Meeting Abstract

P3.73  Sunday, Jan. 6  Elevated Estradiol in Male Fish�\\\\\\\\\\\\\\\” Environmental Differences and Underlying Molecular Mechanisms LARSEN, C.*; REYES, J.A.; IWANSKI, E.; PATEL, R.; KELLEY, K.M.; CSU Long Beach; Pacific Coast Environmental Conservancy; CSU Long Beach; CSU Long Beach; CSU Long Beach larsen.cody@gmail.com

In select locations offshore of urban southern California, males of the fish Pleuronichthys verticalis (hornyhead turbot) have been found to have elevated plasma concentrations of the female steroid, 17β-estradiol (E2). Over years of study, it has been observed that males sampled within Santa Monica Bay (SMB) (offshore of Los Angeles) typically exhibit as much as 10-fold higher E2 levels than males sampled from down-coast locations (e.g., offshore of Orange County). Since estrogens are often at undetectable levels in the environment, even near regional wastewater treatment plant outfalls, it was of interest to determine whether testicular expression of steroidogenic enzymes involved in estrogen production may be altered (by a putative environmental endocrine disruptor?) and linked to endogenous E2 production. Results indicate that gonadal mRNA expression of some steroidogenic genes are relatively higher in testis of fish from SMB, and this is significantly correlated with plasma E2 levels. Furthermore, rearing of high-E2 males in aquaria with clean seawater for 4 and 8 weeks resulted in subsidence of the high estrogen phenotype and testicular expression of steroidogenic genes, down to levels seen in turbot and other flatfish males from outside of the region. New studies are using proteomics to screen for protein expression differences in testis from “high” vs. “control” E2 males, to identify candidate mechanisms underlying the environment-related high E2 phenotype. Additional screening of hepatic protein expression is aimed at identifying potential biomarkers associated with these environments and the high E2 phenotype. (Supported by NOAA/USC Sea Grant Program)