A HYPOLIPIDEMIC PEROXISOME PROLIFERATING FATTY-ACID INDUCES POLYDISPERSITY OF RAT-LIVER MITOCHONDRIA

Primary rat hepatocyte cultures exposed to tetradecylthioacetic acid f or periods up to 96 h significantly increased fatty acid oxidation and decreased triacylglycerol synthesis and secretion. During the same pe riod the mean areal fraction (%) and polydispersity of both mitochondr ia and peroxisomes increased, indicating growth and proliferation. In rats fed tetradecylthioacetic acid for 12 weeks, the fatty acid oxidat ion increased with a concomitant hypolipidemic effect. In addition, th e areal fraction of both mitochondria and peroxisomes increased signif icantly and the number of lipid droplets decreased. The results sugges t that tetradecylthioacetic acid affects mitochondria and peroxisomes both in vitro and in vivo. It is concluded that tetradecylthioacetic a cid reduces secretion of triacylglycerol from rat hepatocytes both in vitro and in vivo mainly by stimulating fatty acid oxidation.