Rapid and effective conversion of 6-keto-prostaglandin F1 alpha to 6,15-diketo-13, 14-dihydro-prostaglandin F1 alpha-immunoreactive material in vivo.
Pentobarbitone-anaesthetized cats were injected i.v. with equal doses of prostacyclin and 6-keto-PGF1 alpha. Subsequently the time course of plasma levels of 6-keto-PGF1 alpha-immunoreactivity (i.r.) and 6,15-diketo-13, 14-dihydro-PGFi alpha-i.r. was determined in arterial blood by specific radioimmunoassays. Injection of both prostacyclin and 6-keto-PGF1 alpha resulted in short lasting peaks of 6-keto-PGF1 alpha-i.r. with maxima after 1 min, which rapidly declined. After injection of prostacyclin plasma 6,15-diketo-13, 14-dihydro-PGF1 alpha-i.r. increased to about one third of the height of the 6-keto-PGF1 alpha-peak and the maximum was reached after 6 min. On the other hand after administration of the same dose of 6-keto-PGFi alpha 6,15-diketo-13, 14-dihydro-PGF1 alpha-i.r. rose to about the same level as the 6-keto-PGF1 alpha-immunoreactive peak and the maximum was already attained after 2 min. When 6,15-diketo-13, 14-dihydro-PGF1 alpha itself was injected no increase in 6-keto-PGF1 alpha-i.r. was seen, whereas the 6,15-diketo-13, 14-dihydro-PGFi alpha-i.r. markedly increased, reaching its maximum after 1 min. These data indicate that in the cat in vivo 6-keto-PGF1 alpha can be rapidly metabolized to a 6,15-diketo-13, 14-dihydro-PGF1 alpha-like compound. The smaller conversion of prostacyclin as compared to 6-keto-PGF1 alpha could be explained by differences in compartmentalization of the two prostaglandins.
D015121:6-Ketoprostaglandin F1 alpha / Q000031:analogs & derivatives* / Q000097:blood*; D000818:Animals; D002415:Cats; D002855:Chromatography, Thin Layer; D011464:Epoprostenol / Q000097:blood*; D005260:Female; D007700:Kinetics; D008297:Male; D011453:Prostaglandins / Q000097:blood*; D011863:Radioimmunoassay
D011453:Prostaglandins; D015121:6-Ketoprostaglandin F1 alpha; C033371:6,15-diketo-13,14-dihydroprostaglandin F1alpha; D011464:Epoprostenol