The Effect of Dietary Fats Containing Trans-Octadecenoates on Calcium Transport and Membrane Properties of The Rat Erythrocyte

Abstract

The response of rat erythrocyte membrane fatty acids to dietary fat of widely differing fatty acid composition was investigated. The red cell fatty acids were susceptible to dietary influence in a very specific manner. An increase of linoleic acid in the diet resulted in higher levels of 9,12-c,c, octadecadienoates in the membrane. The results of the trans-octadecenoate study indicates that the amount of trans fatty acid in the membrane lipids can be correlated to the level of trans acid in the dietary fat. Time studies determined that the equilibrium period for trans-octadecenoate incorporation into cellular lipids is 9 to 12 days. (Ca('2+) + Mg('2+))-ATPase activity using membrane preparations from rats fed trans fatty acids had similar results to experiments using lard as the dietary fat. (Ca('2+) + Mg('2+))-ATPase activity was higher in animals fed diets containing corn oil. The increase in activity was due to an increase in V(,max), and not due to changes in affinity for ATP or Ca('2+). It is suggested that membrane fatty acid fluidity is involved in (Ca('2+) + Mg('2+))-ATPase stimulation.