Synthesis of prostaglandin E2 and prostaglandin F2 alpha by toadfish red blood cells

Saline washed red blood cells of the toadfish convert [1-14C] arachidonic acid to products that cochromatograph with prostaglandin E2 and prostaglandin F2 alpha. This synthesis is inhibited by indomethacin (10 micrograms/ml). Conversion of arachidonic acid to prostaglandin E2 was confirmed by mass spectrometry. When saline washed toadfish red blood cells were incubated with a mixture of [1-14C]-arachidonic acid and [5,6,8,9,11,12,14,15,-3H]-arachidonic acid, comparison of the isotope ratios of the radioactive products indicated that prostaglandin F2 alpha was produced by reduction of prostaglandin E2. The capacity of toadfish red blood cells to reduce prostaglandin E2 to prostaglandin F2 alpha was confirmed by incubation of the cells with [1-14C] prostaglandin E2.