Synthesis of prostaglandins and thromboxane B2 by cerebral arteries.

Abstract

The capacity of cerebral arteries to synthesize prostaglandins was studied by 2 procedures. In 1, bovine cerebral arteries were incubated with 0.1 .mu.Ci (1-14C)-arachidonic acid for 3 h. Using TLC, 5 products of this arachidonic acid were isolated: prostaglandin E2 (PGE2), prostaglandin F2.alpha. (PGF2.alpha.), 6-keto prostaglandin F1.alpha. (6-keto PGF1.alpha.), prostaglandin D2 (PGD2) and thromboxane B2 (TxB2). In the 2nd group of experiments, the biosynthesis of these lipids from endogenous substrate was confirmed, except for PGD2, by GLC-mass spectroscopy. The production of PGE2 and PGF2.alpha. was quantified. An average of 196 ng PGE2 and 172 ng PGF2.alpha. were synthesized per g tissue in 1 h. Meclofenamate inhibited the formation of the 2 prostaglandins while serotonin stimulated synthesis approximately 20%-25%. Cerebral arteries form several prostaglandins and probably thromboxane B2. Apparently, these lipids play a role in the vasomotion of cerebral blood vessels in health and disease. The relative rates of synthesis of these lipids may be important in maintaining normal cerebral circulation. In cerebrovascular disease, the normal balance between the rate of synthesis of those prostaglandins which constrict and those which dilate may be disturbed.