Chemical Structure-Activity Relationships: Peroxisome Proliferation and Lipid Regulation in Rats

Abstract

Studies described here address structure-activity relationships of novel hypolipidemic agents that induce peroxisome proliferation. Male rats were given equivalent doses of three well-studied fibrates, fibrate amides, and structurally dissimilar agents. Aryloxyalkanoic acids, amide analogs, and thio, benzimidazole, phenylpiperazine, and oxazole derivatives induced peroxisome proliferation and decreased plasma cholesterol and triglyceride levels. These compounds contain an acidic function or appear to be readily metabolized to a derivative with an acidic function. Substitution of this substituent with an adamantyloxy eliminated peroxisome proliferation and induced contrasting effects on the lipid profile, substantially increasing triglycerides. A direct correlation was established between hepatocellular peroxisome proliferation and plasma high-density lipoprotein (HDL)+holesterol levels. HY PERLIPLDEMIAThere is strong evidence that plasma high-density lipoprotein (HDL) promotes the removal of cholesterol from extrahepatic tissues, such as the arterial wall, resulting in its ultimate transport to the liver for degradation and excretion (Gordon et al., 1986). The main factor in the development of atherosclerotic plaque is excess low-density lipoprotein (LDL)-cholesterol. Therefore, therapeutic agents are being developed to reduce plasma LDLcholesterol, or to elevate HDL-cholesterol, thus effecting beneficial changes in the lipid profile. While recognizing beneficial health effects, hepatomegaly and hepatic peroxisome proliferation in rodents, as well as hepatocellular carcinoma that ensue after long-term administration, cannot be ignored. Studies addressing chemical structure-