Propionic acid as a precursor in the biosynthesis of animal fatty acids

The carboxyl carbon of propionate was found to be a poor precursor for the synthesis of fatty acids in the rat. The data indicate that propionate as a three-carbon unit is not incorporated into long-chain fatty acids by the intact rat to any appreciable extent. The results suggest that the conversion of propionate to long-chain fatty acids in surviving adipose tissue occurs primarily by a mechanism involving the decarboxylation of the propionate. These data are consistent with the concept that the major lipogenesis pathway in adipose tissue is not different from those described for the liver. There is evidence from the study that a small but significant fraction of the propionate is converted to long-chain fatty acids by adipose tissue in vitro by a mechanism that involves the use of propionate as an intact three-carbon unit. (Author)