Meeting Abstract
87.3 Thursday, Jan. 7 Environment Associated Differences in Male Estrogen Levels and Testicular Steroidogenic Gene Expression in a Southern California Flatfish IWANSKI, E.*; HAGSTROM, K.R.E.; REYES, J.A.; PHAM, M.; KELLEY, K.M.; California State University, Long Beach; California State University, Long Beach; Pacific Coast Environmental Conservancy (pceconservancy.org); California State University, Long Beach; California State University, Long Beach kmkelley@csulb.edu
In Santa Monica Bay offshore of Los Angeles, CA, males of an indigenous flatfish species (hornyhead turbot) exhibit elevated plasma concentrations of 17-beta estradiol (E2) and estrone (E1) as compared with fish residing in other, nearby locations. Our studies are aimed at determining whether this phenotype may be related to a major WWTP outfall in the bay and/or to other environmental or biological factors. This study tested the hypotheses that increased testicular expression of steroidogenic enzymes involved in estrogen production may be associated with the elevated plasma estrogens in males, and that isolation of these fish from the environment may result in amelioration of the high-estrogen phenotype. Gonadal expression of StAR, P450aromatase and 17β-HSD1 measured by qPCR were all significantly higher in testis of fish from Santa Monica Bay as compared with locations only 25-45 km south, along Orange County. In addition, there was an overall significant positive correlation between E2 and E1 concentration and expression of the genes, which was strongest for StAR. Rearing of fish caught from Santa Monica Bay in aquaria containing clean seawater for 4 and 8 weeks resulted in subsidence of the high estrogen phenotype along with testicular expression of the steroidogenic genes, down to levels seen in turbot and other flatfish males from outside of the region that did not have elevated estrogen levels. These findings suggest that environmental factors may drive increased gonadal steroidogenic gene expression and elevated estrogens in male turbot from Santa Monica Bay. (Supported by NOAA – USC Sea Grant Program)
