EXOGENOUS GAMMA-LINOLENIC ACID ALTERS HORMONE-STIMULATED CYCLIC-AMP LEVELS IN U937 CELLS

Polyunsaturated fatty acids are selectively cytotoxic in culture. Inco rporation of these fatty acids leads to profound changes in membrane f atty acid composition which in turn may alter the activity of transmem brane receptor/effector systems. In U937 cells, hormone stimulated pro duction of cyclic AMP can be reduced by 30% following incubation with gammalinolenic acid (18:3n-6). It is suggested that beta-adrenoceptor number, subtype and adenylyl cyclase stimulation may be regulated by a lterations in membrane fatty acid composition as a result of changes i n the levels of polyunsaturated fatty acids and alterations in eicosan oid production.