Meeting Abstract
P2.117 Jan. 5 Stress-induced Cortisol Production and Steroidogenic Enzymes in Wild Flatfish of the Southern California Bight – Potential Impacts of Wastewater Treatment Plant Outfalls HAMILTON, A.**; REYES, J.A.; ARMSTRONG, J.L.; KELLEY, K.M.; California State University, Long Beach; California State University, Long Beach; Orange County Sanitation District; California State University, Long Beach ahamilto@csulb.edu
Stress-induced increases in interrenal production and plasma concentrations of cortisol are transduced through the neuroendocrine hypothalamo-pituitary-interrenal (HPI) axis. In our studies in the Southern Calfornia Bight (SCB), we have observed that some species of flatfish, when sampled from field sites proximal to municipal wastewater treatment plant (WWTP) outfalls, demonstrate significant impairments in the responsiveness of their HPI axis, yielding reduced stress-induced cortisol surges. English sole (Parophrys vetulus) and hornyhead turbot (Pleuronichthys verticalis) exhibit particularly dramatic impairments in their cortisol responses. We have therefore undertaken studies to understand the basis of this failure, with one of the significant hypotheses being that WWTP outfall constituents affect the expression of steroidogenic enzymes necessary for interrenal cortisol synthesis. In addition to other steroidogenic genes, we have cloned cDNAs for 11beta-hydroxylase (P45011beta), the terminal enzyme in cortisol biosynthesis, and 11beta-hydroxysteroid dehydrogenase-type 2 (11beta-HSD-2), which catalyzes the cortisol to cortisone, inactivating the stress signal. All cDNAs from the flatfish species show very high sequence identity with other piscine and mammalian homologs. Results from quantitative real-time PCR assays of interrenal and other tissues of flatfish from WWTP outfall and reference locations will be discussed in relation to potential underlying mechanisms of impairment in the HPI axis. [Supported by Southern California Sea Grant Program NOAA#NA06OAR4170012, project #CE-17]
