Analysis by high performance liquid chromatography of cyclooxygenase products of arachidonic acid metabolism in plasma of rabbits bearing the VX2 carcinoma.

Cyclooxygenase products of arachidonic acid metabolism in the plasma of normal rabbits and animals bearing the VX2 carcinoma were separated by high performance liquid chromatography and the effluent fractions assayed by serologic methods. The products measured were 6-keto-PGF1 alpha, thromboxane B2, PGE2, PGF2 alpha, 13,14-dihydro-PGE2, 13,14-dihydro-15-keto-PGE2, 15-keto-PGE2, and 13,14-dihydro-15-keto-PGF2 alpha. In hypercalcemic, tumor-bearing rabbits, the plasma concentrations of 13,14-dihydro-15-keto-PGE2 and 13,14-dihydro-15-keto-PGF2 alpha were markedly elevated (in the range of 0.5 to 16 ng/ml). Previously unmeasured 6-keto-PGF1 alpha, thromboxane B2, 13,14-dihydro-PGE2 and 15-keto-PGE2 were not found in high concentrations in the plasma of tumor-bearing rabbits. These results add further support to our conclusion that the VX2 tumor produces hypercalcemia in the host by a mechanism which utilizes PGE2, rather than a subsequent metabolite of this prostaglandin, as the mediator between the neoplasm and bone.