Catabolism of 6-keto prostaglandin E1 by rat kidney homogenates

6-Keto prostaglandin E1 (PGE1) was catabolized into two major products by homogenates of rat kidney in the presence of NAD. Rat brain was mostly deficient in this catabolic activity. A total profile of products from these experiments could be obtained using the pentafluorobenzyl esters, O-methyloxime, and trimethylsilyl ether derivatives and analysis by capillary gas chromatography with electron capture detection. The same samples could be effectively analyzed by mass spectrometry using negative ion chemical ionization (NICI) detection. While 6-keto PGE1 showed spasmogenic activity on the rat stomach fundus as well as inhibition of the ADP-induced platelet aggregation, its catabolites lacked such activity. Analysis of rat whole blood by mass spectrometry using the NICI technique showed the presence of small amounts of 6-keto PGE1 and its 15-keto and 15-keto 13, 14-dihydro catabolites in two of eight blood samples.