Abstract
The specific activity of the enzyme palmitoyl-CoA-L-glycerol 3-phosphate palmitoyltransferase (EC 2.3.1.15) in the mammary tissue of guinea pigs has been shown to increase 37-fold at parturition. Increases also occur in tissue concentrations of glycerol 3-phosphate, CoA and free fatty acid, but not in that of acidinsoluble CoA. The isolation and fatty acid composition of plasma triglyceride and of mammary-tissue free fatty acid, diglyceride and triglyceride are described. The findings are discussed in relation to the regulation of milk fat synthesis.