Synthesis of kallikreins by rat kidney slices.

1 Four radioactive akllikreins were isolated from rat kidney slices incubated with (3H)-L-leucine. 2 The kallikreins were purified by procedures previously used for the isolation of rat urinary kallikreins (Nustad & Pierce, 1974), and by affinity chromatography on a column of insolubilized anti-rat urinary kallikrein. 3 The kidney kallikreins resembled the urinary kallikreins in their relative amounts, isoelectric points and electrophoretic mobilities on polyacrylamide disc gels. 4 The data indicate that the kidney synthesizes four kallikreins which are released into urine. The kallikreins are not changed by passage through the lower urinary tract.