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QUANTITATIVE IMAGE CYTOMETRY OF HEPATOCYTES EXPRESSING GAMMA-GLUTAMYL TRANSPEPTIDASE AND GLUTATHIONE S-TRANSFERASE IN DIETHYLNITROSAMINE-INITIATED RATS TREATED WITH PHENOBARBITAL AND/OR PHTHALATE ESTERS
Citation:
Carter, J., R. Richmond, H. Carter, C. Potter, F. Daniel, AND A.B. DeAngelo. QUANTITATIVE IMAGE CYTOMETRY OF HEPATOCYTES EXPRESSING GAMMA-GLUTAMYL TRANSPEPTIDASE AND GLUTATHIONE S-TRANSFERASE IN DIETHYLNITROSAMINE-INITIATED RATS TREATED WITH PHENOBARBITAL AND/OR PHTHALATE ESTERS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/317 (NTIS PB92227586).
Description:
Image cytometry was used to quantify the volume of liver tissue expressing two widely accepted biochemical markers of neoplasia, gammaglutamyl transpeptidase (GGT) and the placental isozyme of glutathione s-transferase (GST-P). ats were treated with hepatocarcinogen, diethylnitrosamine (DENA) alone or combined with phenobarbital (BP). ther groups of rats received either diethylhexylphthalate (DEHP) or di-n-octylphthalate (DOP) in their diets for 26 weeks. GT expression was detected diffusely throughout the liver parenchyma in several treatment groups so that any enhanced expression in AF and M was not apparent. ST-P was detected only in AF and M. ST-P may represent a second genetic alteration as GST-P+ AF and M also expressed GGT but not the reverse. y using the stereologic Principle of Delesse (area%=volume%) and the known liver weight, the grams of tissue expressing either marker was quantified. he peroxisome proliferator, DEHP, inhibited expression of GGT or GST-P in livers of either DENA treated or DENA+PB treated rats. ith GST-P, the reduction was correlated to a reduced number of AF and M. n contrast, DEHP's stereoisomer, POP, was as effective as PB in promoting expression of both markers. e conclude that image cytometry of GST-P expressing hepatocytes can be used in the bioassay of the carcinogenic potential of environmental chemical pollutants.
