Stimulation of arachidonic acid metabolism: Differences in potencies of recombinant human interleukin-1α and interleukin-1β on two cell types

Abstract

Recombinant human interleukin-1 (rIL-1) α and β, which have 26% homology in their amino acid sequence, stimulated arachidonic acid metabolism by squirrel monkey smooth muscle cells and rat liver cells; their relative effectiveness, however, varied with the two cells. Recombinant IL-1α was 3 times more effective than rIL-1β at stimulating arachidonic acid metabolism by the primate smooth muscle cells. Recombinant IL_1α was 3 time less effective than rIL-1β when measured by their capacity to synergistically stimulate arachidonic acid metabolism of rat liver cells in the presence of palytoxin and anti-diuretic hormone (ADH). The rIL-1α and rIL-1β also stimulated the release of radiolabelled arachidonic acid from the smooth muscle cells prelabelled with [ 3H]arachidonic acid. The two recombinant IL-1s have different heat stabilities, again when measured by their capacity to stimulate arachidonic acid metabolism; IL-1α was more heat stable than IL-1β.