Publication Date

2008

Document Type

Thesis

Committee Members

Darrell Fleischman (Committee Member), Lawrence Prochaska (Committee Member), Nicholas Reo (Advisor), Nicholas Reo (Committee Chair)

Degree Name

Master of Science (MS)

Abstract

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) elicits tissue-, sex-, and species-specific effects. This study compares the hepatic response to an oral dose of TCDD in immature ovariectomized (i.o.) C57BL/6 mice (30 µg/kg) and i.o. Sprague-Dawley rats (10 µg/kg), at 72, 120, and 168 h post-dose. Hepatic lipid extracts were analyzed by 13C and 31P NMR, and aqueous extracts by 1H and 31P NMR.

Consistent with increased lipid content in mice (p≤0.05), TCDD induced increases in hepatic triacylglycerides (TAG), cholesterol, and fatty acids. Principal component analysis of 13C spectra show treatment groups separate in mice, but not rats. Mice showed decreases in the lactate/pyruvate ratio and dihydroxyacetone phosphate, consistent with decreased cytosolic NADH/NAD+ ratio and upregulated TAG synthesis. TCDD-treated rats exhibited decreased levels of sphingomyelin, and three-fold increase in phosphocholine, suggesting TCDD activates sphingomyelinase. Both species showed similar decreases in cardiolipin, indicating oxidative stress. These observations are compared with hepatic histopathology and gene expression findings.

Page Count

100

Department or Program

Department of Biochemistry and Molecular Biology

Year Degree Awarded

2008


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