Abstract
The effects of peroxisome proliferators on the levels of rat serum proteins were examined. The proliferators reduced the levels of several proteins in various ways with respect to proliferator-specificity and the time courses of the changes. The identification of three proteins by amino acid sequencing showed that they were functionally unrelated. This diversity suggests that several primary and secondary effects of the peroxisome proliferators caused the various changes in the levels of several serum proteins. Among these, apolipoprotein E was the most but transiently down-regulated by the two proliferators tested. Northern blots of the rat liver mRNA suggested that the primary step of the down-regulation was at pre-translation.