title: Differential production of prostaglandins D2 and E2 and of an unusual prostanoid by chick spinal cord and meninges in vitro.
abstract: In order to specify the source of locally synthesized prostaglandin (PG) E2 which is able to saturate the large class of low affinity PGE2 receptors in chick spinal cord, bioconversion of [1-14C]arachidonic acid into prostanoids was studied in homogenates of chick spinal cord and meninges first without addition of exogenous glutathione (GSH). Homogenates of spinal cord produced 14C-labeled PGE2, PGD2 and PGF2 alpha. Homogenates of meninges accumulated much larger amounts of [14C]PGE2 than spinal cord and surprisingly a 14C-labeled arachidonate metabolite referred to as compound Y. Compound Y generation, which was inhibited by indomethacin and enhanced by esculetin, was therefore mediated through the cyclooxygenase pathway. The fact that no labeled compound Y was detected in homogenates incubated with [3H]PGD2 or [3H]PGE2 indicated that compound Y was not a degradation product of PGs. Secondly, after addition of exogenous GSH, 14C-labeled compound Y was totally converted into [14C]PGE2. The compound Y which is converted into PGFs after a strong reduction with NaBH4 and into PGE2 after a mild reduction with GSH-hemin system or SnCl2 was therefore assumed to be a 15 hydroperoxy-PGE2 (15 HP-PGE2). These results suggest that PGE2 can be synthesized in meninges either by the classical isomerization of PGH2 or by isomerization of PGG2 followed by a GSH-sensitive reaction.
authors.affiliation: Institut d'Histologie et d'Embryologie, Faculté de Médecine, Université de Lausanne, Switzerland.
authors.forename: M F
authors.initials: MF
authors.lastname: Vesin
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D001894:Borohydrides / Q000494:pharmacology; D002645:Chickens; D015237:Dinoprost / Q000096:biosynthesis; D015232:Dinoprostone / Q000031:analogs & derivatives* / Q000096:biosynthesis*; D005978:Glutathione / Q000494:pharmacology; D066298:In Vitro Techniques; D008578:Meninges / Q000378:metabolism*; D015230:Prostaglandin D2 / Q000096:biosynthesis*; D013116:Spinal Cord / Q000378:metabolism*
chemical_list: D001894:Borohydrides; D016718:Arachidonic Acid; C048495:15-hydroperoxyprostaglandin E2; C025364:sodium borohydride; D015237:Dinoprost; D005978:Glutathione; D015232:Dinoprostone; D015230:Prostaglandin D2