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MOLECULAR CHARACTERIZATION OF ENDOCRINE DISRUPTION IN FISH USING CDNA ARRAYS.
Denslow, N, P. Larkin, T. SaboAttwood, M J. Hemmer, AND L C. Folmar. MOLECULAR CHARACTERIZATION OF ENDOCRINE DISRUPTION IN FISH USING CDNA ARRAYS. SETAC 23 Annual Meeting in North America, Salt Lake City, UT, Nov 16-20, 2002.
We are developing cDNA macroarrays to measure the induction of gene expression in sheepshead minnows and largemouth bass exposed to anthropogenic chemicals that can mimic the action of endogenous hormones. For sheepshead minnows exposed in aqua, we observed similar genetic profiles with the strong estrogens 15-beta estradiol, 17-alpha ethynylestradiol, diethylstibestrol, and the weak estrogens methoxychlor, and p-nonylphenol, but not with endosulfan, which looked more like the controls. Some genes were differentially regulated with p-nonyl phenol (up-regulation of ubiquitin-conjugating enzyme 9) and endosulfan (up regulation of ER alpha and down-regulation of 3-hydroxy-3-methylglutarylCoA reductase). For largemouth bass, we have developed a BassChip containing probes for 132 genes. One mechanism by which some environmental contaminants influence the reproductive system is by inducing the estrogen receptor cascade at inappropriate times. We are using the BassChip to monitor natural changes in gene expression in females across the reproductive season to determine baseline expression levels for estrogen responsive genes. We are also determining the changes induced by exposure to p-nonylphenol in male fish and by exposure to 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p-DDE) in both male and female fish. Initial experiments suggest that p,p-DDE has differential effects in males and females. The arrays are also useful to monitor dose-dependent changes in mRNA expression. We see differential regulation of several estrogen-sensitive genes when ethinylestradiol is increased from 20 ng/L to 1000 ng/L, suggesting unique sensitivities for some of the genes. Overall, this research suggests that a better understanding of the consequences of exposure can be obtained from monitoring multiple genes at one time.