Misidentification of prostamides as prostaglandins.
Prostaglandins and endogenous cannabinoid metabolites share the same lipid backbone with differing polar head groups at exactly the position through which a large molecule is attached to provide antigenicity and thus raise antisera. Hence, we hypothesized that antisera raised against prostaglandins linked to a large molecule such as BSA at the carboxyl functional group would also recognize endogenous cannabinoid metabolites and lead to highly misleading interpretations of data. We found major cross-reactivity of commercial antisera raised to prostaglandins with endocannabinoid metabolites. Furthermore, in a well-characterized cell line (WISH) or primary amnion tissue explants, endocannabinoid treatment led to increased production of endocannabinoid metabolites as opposed to primary prostaglandins. This was apparent only after separation of products by thin-layer chromatography, because they measured as prostaglandins by radioimmunoassay. These findings have major implications for our interpretation of data in situations in which these prostaglandin-like molecules are formed, and they stress the need for chromatographic or spectrometric confirmation of prostaglandin production detected by antibody-based methods.
Glass
Michelle
M
Department of Pharmacology, University of Auckland, Auckland, New Zealand. m.glass@auckland.ac.nz
Hong
Jiwon
J
Sato
Timothy A
TA
Mitchell
Murray D
MD
D000650:Amnion / Q000166:cytology; D001095:Arachidonic Acids / Q000378:metabolism; D063385:Cannabinoid Receptor Modulators / Q000276:immunology; D002478:Cells, Cultured; D002855:Chromatography, Thin Layer / Q000379:methods; D003429:Cross Reactions; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000276:immunology; D063388:Endocannabinoids; D005260:Female; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D008565:Membrane Proteins; D053284:Polyunsaturated Alkamides; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis; D011453:Prostaglandins / Q000276:immunology*; D011863:Radioimmunoassay
D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D007375:Interleukin-1; D008565:Membrane Proteins; D053284:Polyunsaturated Alkamides; D011453:Prostaglandins; C107684:prostaglandin E2 ethanolamide; C493494:prostaglandin F2alpha ethanolamide; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone; C078814:anandamide