Abstract
Action of parotin on the circulating leukocytes of a rabbit was examined and the following facts were found. 1) Intravenous injection of parotin in rabbits resulted in the leukocytosis-promoting activity in the serum 4-6 hr later. 2) The leukocytosis-promoting factor in the rabbit serum after administration of parotin is inactivated by heat treatment at 100°for 5 min, but is a stable, non-dialyzable substance after heat treatment at 56°for 30 min or at 37°for 60 min. 3) The leukocytosis-promoting factor was isolated from the serum after parotin administration, using ammonium sulfate fractionation, DEAE-cellulose column chromatography, gel filtration over Sephadex G-200, isoelectric focusing with carrier ampholyte, and preparative slab disc electrophoresis. It was found that this factor has a molecular weight of ca. 160000 by gel filtration over Sephadex G-200 and disc electrophoresis, and has an isoelectric point at pH 5.02. The factor is not stained by basic fuchsin. From sodium dodecyl sulfate treatment, this factor was considered to be formed from two subunits with a molecular weight of ca. 80000. This factor was found to be immunochemically different from parotin.
