Modulations of hepatic gamma-glutamyltranspeptidase and N-hydroxy-N-2-fluorenylacetamide sulfotransferase activities following treatment of rats with a hepatocarcinogenic regimen: effect of partial hepatectomy.
The feasibility of using biochemical assays of gamma-glutamyltranspeptidase (gamma-GTP) and N-hydroxy-N-2-fluorenylacetamide sulfotransferase (N-OH-2-FAA ST) activities to monitor the effects of treatment of male Sprague-Dawley rats with a two-stage hepatocarcinogenic regimen was investigated. One week after initiation with diethylnitrosamine (200 mg/kg of bw), the rats were treated with 10 oral doses within 2 weeks of N-2-fluorenylacetamide (2-FAA) at 0.05 mmole/kg or vehicle (corn oil) at 5 ml/kg of body weight. After five doses of 2-FAA or corn oil, half of the rats in each group underwent partial (70%) hepatectomy (PH). Three days after completion of 2-FAA treatment, gamma-GTP activity increased approximately 8-fold in the livers of both the nonhepatectomized (-PH) and hepatectomized (+PH) groups. After 17 days, the enzyme activity decreased to the control level in the -PH group but increased 3.1-fold above the control level in the +PH group. After 31, 66, and 87 days, gamma-GTP activity increased only 1.4- to 2.6-fold in the -PH group, whereas that of +PH group increased 15- to 32-fold. N-OH-2-FAA ST activity, determined 3 days after completion of 2-FAA treatment, decreased by approximately 60% in the -PH and +PH groups. After 17 days, the effect of PH became evident in that the losses of N-OH-2-FAA ST activity were smaller (20%) in the -PH than in the +PH group (45.5%). After 31, 66, and 87 days, the respective decreases of 27, 29, and 41% in the +PH group were significant.(ABSTRACT TRUNCATED AT 250 WORDS)
Vijayaraghavan
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P
Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis.
Malejka-Giganti
D
D
D000818:Animals; D006498:Hepatectomy; D006881:Hydroxyacetylaminofluorene / Q000378:metabolism*; D008099:Liver / Q000201:enzymology* / Q000601:surgery; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000201:enzymology* / Q000601:surgery; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
D006881:Hydroxyacetylaminofluorene; D005723:gamma-Glutamyltransferase