Decreased cyclic AMP accumulation in lymphocytes in response to adrenaline and prostacyclin after n-3 polyunsaturated fatty acid supplementation in man.

The effect of supplementation with n-3 polyunsaturated fatty acids on beta-adrenoceptor function in lymphocytes has been studied in ten healthy male volunteers. Ten Max-Epa capsules containing 320 mg n-3 polyunsaturated fatty acids per capsule were given for 3 weeks, and the cyclic AMP accumulation response in lymphocytes to adrenaline and the prostacyclin analogue iloprost (ZK 36374) were assessed before and after supplementation. After supplementation about 30% less cAMP was accumulation by the lymphocytes in response to either adrenaline or iloprost. Propranolol inhibited the adrenaline-induced increase in cAMP both before and after supplementation, but the difference in the basal cAMP concentration between the groups still persisted. Adrenaline stimulation after pre-incubation of the lymphocytes with the alpha-adrenoceptor antagonist phentolamine resulted in an even more pronounced difference between pre- and post-supplementation cAMP concentrations. The results suggest that fish oil supplementation may lead to decreased responsiveness of adenylate cyclase to catecholamine and prostaglandin stimulation.