Radioautographic Study on the Intracellular Localization of Bezafibrate in Cultured Rat Hepatocytes.

Abstract

In order to demonstrate the intracellular localization of the peroxisome proliferator in the hepatocytes, we have examined the localization of silver grains due to 14C-labeled bezafibrate in cultured rat hepatocytes by means of light and electron microscopic radioautography. On light microscopic radioautograms of the epoxy resin sections at each incorporation period, about 90% of all the silver grains were localized over the cytoplasmi Then, statistical significance was evaluated on grain density in the cytoplasm. On electron microscopic radioautograms of whole mount cultured cells observed by high voltage electron microscopy, silver grains were localized on the cytoplasmic matrix, especially over the endoplasmic reticulum. From these results, it is concluded that bezafibrate was localized over the endoplasmic reticulum. This fact suggests than the receptor of peroxisome proliferator should be associated with the endoplasmic reticulum or the receptor exists on the endoplasmic reticulum. Thus, it is demonstrated that the peroxisome proliferator acts on the endoplasmic reticulum of hepatocytes to proliferate peroxisomes.