Response of microbodies in Morris hepatoma 9618A to clofibrate.

Regulation of the formation of microbodies in Morris hepatoma 9618A was studied by examination of the response of the organelles to clofibrate. The fine structures of microbodies in the hepatoma cells closely resembled those in hepatocytes of normal adult rats. In clofibrate-treated rats, the tumor cells showed a slight increase in the size of microbodies and in catalase activity; however, the tumor microbodies did not increase in number. In contrast, in adult clofibrate-treated rats and rats on the day of birth whose mothers received clofibrate during the gestation period, the hepatocytes showed microbodies that were greater in both number and size, and the catalase activity in the liver was definitely elevated.