Effects of some hypolipidemic drugs and phthalic acid esters on fatty acid binding protein in rat liver.

Effects of clofibric acid, probucol, niceritrol, di-(2-ethylhexyl)phthalate (DEHP) and dibutyl phthalate (DBP) on the binding capacities of fatty acid binding protein (FABP) and ligandin fractions in rat liver were investigated. The binding capacity of FABP fraction in male rat liver to oleic acid was increased remarkably on clofibric acid-feeding for 7 d. The administration of either probucol or niceritrol had little influence on the binding capacity of FABP. Both DEHP and DBP increased the binding capacity of FABP in liver of male rats, but the extent of the increase was somewhat less significant in DEHP- or DBP-fed rats compared to that in clofibric acid-fed rats. Sex-related difference in the increase in the binding capacity of FABP fraction to oleic acid by either clofibric acid or DEHP was observed and the extent of the increase in female rats feeding clofibric acid or DEHP was about half of male rats. Effects of any drugs and agents tested here on the binding capacity of ligandin in liver to bromosulfophthalein (BSP) were little if any. The increase in the binding capacity of FABP fraction, but not ligandin in liver was confirmed in vivo by intravenous administration of BSP to rats which had been fed DEHP. In spite of marked increase in the binding capacity of FABP fraction in liver from clofibric acid-fed rats, no remarkable increase in the incorporation of radioactive oleic acid into esterified lipids was observed in vivo.