Polyunsaturated fatty acids inhibit Mg2+-ATPase in basolateral membranes from rat enterocytes

It is known that certain polyunsaturated fatty acids of the n-6 family, for example linoleic and arachidonic acids, can activate both Na+, K+-ATPase a nd Ca2+-ATPase. These enzymes drive active absorption processes in the duod enal enterocyte. This study presents data which show a 30-50% inhibition of Mg2+-ATPase activity in enterocyte basolateral membrane preparations by li noleic and gamma-linolenic acids (also a member of the n-6 family.) Mg2+-ATPase activity has several possible roles in the enterocyte: involvem ent in Mg2+ and Ca2+ absorption (as part of Ca2+-ATPase and also myosin I a ctivity) as well as control of phospholipid distribution in the membrane by a class of Mg2+-ATPases called 'flippases'. The action of linoleic and gam ma-linolenic acids on basolateral membrane Mg2+-ATPase may thus modulate se veral cellular transport processes.