A histochemical study of glycogen alterations in the livers of rats following azo dye administration.

Abstract

1. Liver glycogen storage has been studied histochemically in rats after treatment with 3′-methyl-4-dimethylaminoazobenzene for periods of 2–30 days. The results were compared with those obtained by a chemical procedure on the same livers. Related azo dyes and other hepatotoxic agents were studied in an effort to determine the nature and significance of the glycogen changes observed. 2. All animals which had been fed 3′-Me-DAB for at least 14 days showed sharply demarcated areas of centrolobular glycogen depletion which involved as much as 50 per cent of the total liver in some cases. All pair-fed control animals showed an even lobular distribution of liver glycogen, although the total staining capacity of the livers varied greatly. The glycogen-depleting effect of 3′-Me-DAB was observed to take place as early as 11 days in some animals and appeared to reach its maximum just before the onset of bile-duct proliferation. 3. Similar changes in glycogen storage were observed to result from administration of ethionine, thioacetamide, carbon tetrachloride, and, to a lesser degree, 4-dimethylaminoazobenzene, but not from the noncarcinogenic dyes 2-methyl-4-dimethylaminoazobenzene and 4-aminoazobenzene.