Turnover of ribosomal proteins in regenerating rat liver after partial hepatectomy

Abstract

1. 1. The rates of synthesis and degradation of ribosomal proteins, prelabelled with [ 14C]bicarbonate, were determined as an index of the rate of ribosome turnover in regenerating rat liver. 2. 2. The half-life of ribosomes is about 178 and 75 hr in regenerating and normal liver, respectively. 3. 3. The comparison of turnover rates of ribosomal proteins with the corrected values of rRNA, based on re-utitilization of nucleotides, suggests that ribosomes are metabolized as a unit in vitro. 4. 4. There is at least 70% overestimation for ribosome half-life when orotate-labelled RNA is used for turnover determinations. 5. 5. The absolute rate of synthesis is estimated as 3925 and ribosomes/min per cell in 24 hr regenerating and normal rat liver, respectively.