Lactate as a precursor of fatty acids in bovine adipose tissue

In vitro experiments were conducted to determine the rates of lactate, acetate, and glucose conversions to glycerol, CO2, and fatty acids by subcutaneous adipose tissue of cattle. To study the pathway for lactate utilization as a carbon source for lipogenesis, the effect of each of four substates (lactate, acetate, pyruvate, and glucose) on the rate of conversion of the other three was determined. The rates of lactate conversion to fatty acids and to glycerol were greater than those for acetate and glucose. Acetate, however, was oxidized to CO2 at greater rates than either lactate or glucose. Acetate was used for fatty acid synthesis at greater rates than pyruvate was less than that from lactate but greater than that from glucose. Acetate additions to the incubation media decreased the synthetic rates from lactate, pyruvate, and glucose. Pyruvate decreased rates of fatty acid synthesis from glucose but slightly (not statistically significant) stimulated synthesis from lactate and acetate. Lactate decreased glucose and pyruvate utilization but had no effect upon that of acetate. Our results clearly demonstrated that lactate can be used for fatty acid synthesis as well as for glycerogenesis by bovine adipose tissue.