title: The effect of enkephalins and prostaglandins on O-2 release by neutrophils.
abstract: Derivatives of superoxide (O-2), produced by phagocytic cells, are thought to play a role in the adult respiratory distress syndrome (ARDS) and other disease states. Control of the release of O-2 may prove beneficial. Using human neutrophils as a source of O-2, and an assay for O-2 based upon the reduction of cytochrome C, we found that prostaglandin D2 (PGD2), leucine enkephalin (LE), and methionine enkephalin (ME) inhibited O-2 release. The Escherichia coli product, N-formyl methionyl leucyl phenylalanine (FMLP), was employed to stimulate O-2 release. PGD2 was most potent while there was no significant difference between LE and ME. Another peptide, thyrotropin releasing hormone (TRH), had no effect on O-2 release. There was no correlation between the potency of the inhibitory effect on O-2 release and the effect of these agents on the binding of [3H] FMLP to human neutrophils. Comparison of different but structurally related prostaglandins (PGD2, PGE2, and PGF2 alpha) revealed that PGD2 was more potent than PGE2 in inhibiting O-2 and that PGF2 alpha had no effect. This result suggested that the presence and position of the carbonyl group was an important determinant of the magnitude of inhibition.
mesh_terms: D015232:Dinoprostone; D004743:Enkephalin, Leucine / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000494:pharmacology; D004745:Enkephalins / Q000494:pharmacology*; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000097:blood / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D015230:Prostaglandin D2; D011453:Prostaglandins / Q000494:pharmacology*; D011457:Prostaglandins D / Q000494:pharmacology; D011458:Prostaglandins E / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013481:Superoxides / Q000097:blood*
chemical_list: D004745:Enkephalins; D011453:Prostaglandins; D011457:Prostaglandins D; D011458:Prostaglandins E; D013481:Superoxides; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D009240:N-Formylmethionine Leucyl-Phenylalanine; D015232:Dinoprostone; D015230:Prostaglandin D2