Early appearance of embryonic -globulin in rat serum during carcinogenesis with 4-dimethylaminoazobenzene.

ABSTRACT

PIP Heptatic tumors were induced in male Donryo rats by feeding them a 4-dimethylaminoazobenzene diet to study the occurrence of serum alpha globulin (AG) in rats during carcinogenesis. AG was found in rat serum as early as the 3rd week after onset of feeding of the carcinogenic diet; this was designated the early-stage appearance. The embryonic protein was observed in 31 (76%) of 41 rats at the 6th week after diet introduction. Subsequently, concentrations of AG decreased, and by the 11th-12th week it disappeared from serum. After 13 weeks, the developmental protein reappeared in 27/33 rats, designated the last-stage appearance, and 26 of these animals developed hepatomas. Of the 22 rats in which AG appeared in the early stage, 20 (91%) developed hepatomas after 19 weeks. By the 6th week of the carcinogenic diet, the average serum level of AG was 2-4 mg/dl, but after 13 weeks, it reached 60-100 mg/dl, corresponding to the serum level of newborns. Since most of the rats in which AG appeared at the early stage developed hepatomas, the early appearance of the protein may be related to cancerization of liver cells; on the other hand, the early appearance of AG may simply reflect an acute liver lesion caused by the toxicity of 4-dimethylaminoazobenzene. All rats that developed hepatomas were AG positive.^ieng