| Abstrakt: |
We report changes in biomarker enzymes (cytochrome P4501A, glutathione-S-transferase) and protein expression (cytochrome P4501A) in adult painted turtles, Chrysemys picta, as part of a study of the potential impact of contaminants originating from the Massachusetts Military Reservation on Cape, Cod, MA. In animals from both Moody Pond, a site potentially impacted by contaminants, and Washburn Pond, a nonimpacted site, rates of hepatic microsomal ethoxyresorufin-O-deethylase (EROD) activity were very low yet differences were detected. In Moody Pond, rates in both females and males peaked in June (4.3 ± 0.5 pmol min[sup -1] mg[sup -1] and 5.9 ± 1.5 pmol min[sup -1] mg[sup -1] (mean ± sem) respectively). At Washburn Pond, EROD rates in males peaked in May (3.8 ± 0.6pmol min[sup -1] mg[sup -1]), and in females were highest in August (2.5 pmol min[sup -1] mg[sup -1]). There were differences in EROD rates between turtles from the two locations (ANOVA; p<0.05), with higher activity at the impacted site. Western blot analysis for CYP1A protein showed a seasonal pattern of expression at the impacted site and a significant difference in expression between the two sites in June, with values being higher at the potentially impacted site (p<0.05). Hepatic cytosolic GST activity, measured by 1,2-chlorodinitrobenzene conjugation, also showed a seasonal pattern in females, but not males. In Moody Pond, rates in females were highest in June (8.05 ± 1×10[sup -5] µmol min[sup -1] mg[sup -1]) and rates in males were highest in July (7.74 ± 2×10[sup -5] µmol min[sup -1] mg[sup -1]). Rates were highest in females from Washburn Pond in May (8.2 ± 1.1×10[sup -5] µmol min[sup -1] mg[sup -1]) and, in males in June (6.63 ± 1×10[sup -5] µmol min[sup -1] mg[sup -1]). There was no significant difference in activity between males and females, but there were significant (p<0.05) differences between females from the two sites, with activity being higher at the potentially impacted site. The elevated activity of hepatic enzymes at the impacted site indicates that responses to unidentified pollutants or pollutant mixtures are superimposed upon a normal seasonal rhythm of enzyme activity at this location. [ABSTRACT FROM AUTHOR] |
