Regulatory role of prostaglandins in the vascular system.

It is reported that noradrenaline-induced vasoconstriction initiates generation of prostaglandins of the E series by vasculas walls. These endogenous prostaglandins attenuate the vasoconstrictor effect of noradrenaline. Inhibitors of prostaglandin biosynthesis (indomethacin, mefenamic acid) abolish acute tolerance to noradrenaline infusions and counteract hypotension which is induced in cats by injection of endotoxin or by injection of rat blood.