Synthesis of α1‐Microglobulin by Guinea‐Pig Liver

Abstract

Explants from perfused guinea pig livers released .alpha.1-microglobulin (.alpha.1-M) into the culture medium. 3H-Leucine in the medium was incorporated into the protein, suggesting a de novo synthesis of .alpha.1-M by the liver tissue. The size of the protein could not be distinguished from that of purified urinary .alpha.1-M when tested with sodium dodecyl sulfate/polyacrylamide gel electrophoresis. After i.v. injections of 3H-leucine into guinea pigs, the 105,000 .times. g pellet of homogenized liver rapidly increased its content of radioactive .alpha.1-M, with a maximum after 20 min. 3H-Labeled .alpha.1-M appeared in serum after a lag phase of 20 min, and by comparing the rate of accumulation with albumin, the synthesis of guinea pig .alpha.1-M could be estimated to 20 .mu.g g liver-1 h-1.