Abstract
The significance of liver enlargement induced by various chemicals was studied. Biochemical changes of principal hepatic components and enzymes were compared under the short-term administratior, to male rats for 5 days that did not cause the retardation of growth of the treated animals. Polychlorinated biphenyls (PCB, administered dietary) was most potent in inducing liver enlargement, followed by 3-methylchlolanthrene (MC, i.p.), AF-2 (furylfuramide, dietary), phenobarbital (PB, i.p.), and di-2-ethylhexyl phthalate (DEHP, dietary). The biochemical parameters of the liver were affected in a different manner by these chemicals under the condition that caused the increase in the liver weight to the same level. The observed changes in the liver showed three patterns of response : drug-metabolisminducer type, AF-2 type and DEHP type. The differences of these three types were mainly observed in respect to the drug-metabolizing enzyme activity, glycogen and lipid contents and the appearance of hyperplasia or hypertrophy. The significance of these types of response is discussed in relation to toxicity, dysfunction, and adaptation of the liver.
