Liver regeneration in rats partially hepatectomized following massive organ enlargement induced by thianthrene.

Male rats were fed a diet supplemented with 0.12% thianthrene or control chow for a period of 10 days after which they were partially hepatectomized, two-thirds of the organ being removed and continued on the diet or switched to the other for the last 10 days. All animals were sacrificed on day 20 and the extent of liver regeneration determined. Intact males were also employed and the wet- and dry-liver weight percentages compared. The thianthrene diet administered for 20 days or p.o. for 10 days elicited extensive regeneration but the effect did not extend to the group switched to the control ration. With the latter, the portion undergoing regeneration was markedly lower owing to the massive amount of tissue extirpated at surgery. The test agent was very stimulatory to the intact male including the group placed on the control diet for the last 10 days. For animals fed thianthrene for 20 days, liver microsomal cytochrome P-450 and aminopyrine demethylase were elevated significantly in the intact series and the last enzyme, in the operated males; the difference in benzo[a]pyrene hydroxylase was not remarkable in either series.