Octanoate inhibits very low-density lipoprotein secretion in primary cultures of chicken hepatocytes

The effects of octanoate, a medium-chain fatty acid, on very low-density lipoprotein (VLDL) secretion in primary cultures of chicken hepatocytes were compared with those of palmitate. Palmitate added to the incubation media at concentrations up to 0.36 mM increased intracellular triacylglycerol (TG) accumulation and VLDL-TG secretion in a concentration-dependent manner, whereas the addition of octanoate alone (0.21-0.6 mM) did not change these parameters. VLDL-TG secretion from hepatocytes cultured in media to which 0.6 or 1.0 mM octanoate had been added in the presence of 0.21 mM palmitate was significantly lower than that obtained under control incubation conditions (0.21 mM palmitate only). The addition of 1.0 mM octanoate to the incubation media with or without 0.21 mM palmitate decreased VLDL apolipoprotein B (apoB) secretion. These results demonstrate that the addition of octanoate to primary cultures of chicken hepatocytes reduces VLDL secretion in respect of both TG and apoB secretion. It is suggested that medium-chain fatty acids are a factor modulating VLDL secretion, which plays a key role in fat deposition in chickens.