Effects of arachidonic acid on rat gastric acid secretion in response to different secretogogues; inhibition of these effects by indomethacin.

1 The effects of the prostaglandin precursor, arachidonic acid, and the non-steroidal anti-inflammatory drug, indomethacin, on gastric acid secretion were studied in the rat, in vivo and in vitro. Gastric mucosal blood flow was also measured in vivo. 2 Arachidonate produced significant inhibition of acid secretion stimulated by pentagastrin or histamine. It did not significantly affect dibutyryl cyclic adenosine 3',5'-monophosphate (db cyclic AMP)-induced acid secretion. 3 Inhibition of acid secretion by arachidonate was accompanied by a rise in the ratio of mucosal blood flow to acid secretion. 4 Indomethacin did not significantly alter histamine- or pentagastrin-induced acid secretion. 5 In the presence of indomethacin, the inhibitory effect of arachidonate was significantly reduced. 6 These results provide evidence that the rat gastric mucosa is capable of synthesizing, from exogenous precursor, products of cyclo-oxygenase which inhibit gastric acid secretion.