Biosynthesis of prostaglandins in rabbit renal cortex

Prostaglandin biosynthetic activity has been found in the microsomal fractions prepared from rabbit renal cortex. The cortex preparation requires arachidonic acid as substrate and hydroquinone and reduced glutathione as cofactors for enzymatic activity and is inhibited by indomethacin. The biosynthetic capacity of the washed microsomes of cortex ranges from one third to equal that of the washed microsomes of medulla. A partially purified medullary cytoplasmic factor and crystalline hemoglobin can stimulate greatly the synthetase activity in the microsomes of the medulla, but they have no effect on the activity of cortical microsomes.