Role of the kidney in plasma albumin catabolism

Abstract

The role of kidneys in the breakdown of plasma albumin was investigated. The rate of iodoalbumin breakdown by bilaterally nephrectomized rats and in isolated perfused rabbit kidney were studied. Homologous I 131 -labeled plasma albumin was used. To remove denatured components, the iodoalbumin was ‘screened,’ that is, it was injected into animals which were bled several days later, and whole plasma was used as the iodoalbumin substrate. It was found that bilateral nephrectomy reduced unscreened iodoalbumin breakdown by about 20% but had no effect on the breakdown of screened iodoalbumin. Unscreened iodoalbumin was broken down at an appreciable rate by perfused kidney, but with screened iodoalbumin the breakdown rate was greatly reduced. It is concluded that, at most, 10% of the turnover of native plasma albumin in the body may occur in kidneys.