Suppression of EGF binding in rat liver by the hypolipidemic peroxisome proliferators, 4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio-(N-beta-hydroxyethyl)ac etamide and di(2-ethylhexyl)phthalate.

Dietary administration of 4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio(N-beta-hydroxyethyl) acetamide(BR931) and di(2-ethylhexyl)phthalate (DEHP), hypolipidemic agents, to rats for 3-35 days induced a marked reduction in the hepatocyte surface and intracellular binding of [125I]EGF without affecting its binding affinity. The reduction was apparent after 3 days' feeding of BR931 and the magnitude of the reduction was consistently higher in hepatocytes of BR931-treated rats than those of DEHP-treated rats. The liver extracts and the sera from rats fed BR931 or DEHP for 4 weeks showed no inhibitory effects on the EGF binding of hepatocytes from rats fed a basal diet. Possible significance of the changes in relation to their hepatocarcinogenic action was discussed.