IN-VITRO ACTIVATION AND INHIBITION OF RAT COLONIC PHOSPHOLIPASE-D BY FATTY-ACIDS

The present study was designed to examine the effect of long-chain fat ty acids on phospholipase D (PLD) of the proximal colon mucosa of the rat. These fatty acids are present in the colon, in close contact with the membranes which contain the enzyme. The results indicate that uns aturated fatty acids activate the enzyme. At 4 mM, trienes are more po tent activators as compared to 18:2 and 18:1. The number of double bon ds and the configuration around the double bond were found to be impor tant factors in activation of the enzyme. The metabolism of polyunsatu rated fatty acids may be involved in the activation since the presence of antioxidants and cyclooxygenase inhibitors were found to influence the activation of PLD by polyunsaturated fatty acids.