Segregation of an Intravenously Injected Protein by "Droplets" of the Cells of Rat Kidneys

The ability of the "droplets" of kidney cells to segregate proteins is suggested by the work of Gerard and Cordier (I), Smetana and Johnson (2), Oliver, MacDowell, and Lee (3), Rather (4), and others. The question arises as to how the segregating ability of the droplets is related to the function of the enzymes (acid phosphatase, ribonuclease, desoxyribonuclcase, cathepsin, and/3-glucuronidase) which have been found to be highly concentrated in the droplets (5, 6), and how it is related to the changes occurring after intraperitoneal injection of egg white. As reported in a preceding paper (7) it was observed that the injection of egg white caused the development of large droplets (1 to 5 # diameter) from small droplets (0.1 to 1.0 /z diameter) and the concomitant release of acid phosphatase, cathepsin, ribonuclease, and desoxyribonuclease from the droplets. The increased content of cathepsin, acid ribonuclease, and deoxyribonuclease in the total homogenate suggested a resynthesis of these enzymes after their release by the droplets (7). The uptake of fluid and solid particles (so called pinocytosis and athrocytosis) is probably a more general ability of