Existence of an enzymatic pathway furnishing arachidonic acid for prostaglandin synthesis from arachidonoyl CoA in rabbit kidney medulla.
We examined whether arachidonoyl CoA (AA-CoA) can be a possible supplier of arachidonic acid (AA) for prostaglandin (PG) synthesis in rabbit kidney medulla. AA-CoA was preincubated with or without the 105,000 g supernatant (cytosol) fraction from the kidney medulla for 5 min at 37 degrees C followed by the incubation with the microsomal fraction (0.5 mg protein) (a rich source of PG synthesizing enzymes) in the presence of reduced glutathione and hydroquinone for 5 min at 37 degrees C, and the formed PGE2, F2 alpha and D2 were measured by high-pressure liquid chromatography using 9-anthryldiazomethane for derivatization. The addition of AA-CoA (20 nmol) alone changed the total PG formation (the sum of PGE2, F2 alpha and D2) from 0.14 to 1.55 ng. When the cytosolic fraction (10-100 microliters) was added together with 20 nmol-AA-CoA in the preincubation mixture, total PG formation was further increased 2- to 3-fold compared to AA-CoA alone. Experiments utilizing AA, instead of AA-CoA and boiled cytosolic fraction revealed that the stimulatory action of the cytosolic fraction on the AA-CoA-induced PG synthesis may not be due to the effect on cyclooxygenase activity and due to long-chain acyl CoA hydrolase. These results show that long-chain acyl CoA hydrolase which hydrolyzes AA-CoA to AA is present in the cytosol of rabbit kidney medulla and suggest that this enzyme activity is a potential mediator of supply of AA for PG synthesis in this region.
Sakuma
S
S
Department of Hygienic Chemistry, Osaka University of Pharmaceutical Sciences, Japan.
Fujimoto
Y
Y
Doi
K
K
Nagamatsu
S
S
Nishida
H
H
Fujita
T
T
D000214:Acyl Coenzyme A / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003600:Cytosol / Q000201:enzymology; D015237:Dinoprost / Q000096:biosynthesis; D015232:Dinoprostone / Q000096:biosynthesis; D005978:Glutathione / Q000494:pharmacology; D006873:Hydroquinones / Q000494:pharmacology; D007679:Kidney Medulla / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D008297:Male; D008861:Microsomes / Q000201:enzymology; D015230:Prostaglandin D2 / Q000096:biosynthesis; D011453:Prostaglandins / Q000096:biosynthesis*; D011817:Rabbits
D000214:Acyl Coenzyme A; D006873:Hydroquinones; D011453:Prostaglandins; C026563:arachidonyl-coenzyme A; D016718:Arachidonic Acid; D015237:Dinoprost; D005978:Glutathione; D015232:Dinoprostone; D015230:Prostaglandin D2; C031927:hydroquinone