Uptake of lysine and incorporation into proteins of the cortex during a short-term hypoxia of neonatal rats.

The uptake of [14C]lysine and its incorporation into proteins of the brain cortex was determined in vivo during a mild hypoxia (pO2 = 10.5-11.0 kPa) for short times up to 120 min in newborn rats. The uptake was relatively high within the first 15 min and was not altered by hypoxia. A diminished incorporation of lysine by about 20% was measured in the early phase of hypoxia. Later on the incorporation of the radioactive amino acid increased and reached control values. All investigated subcellular fractions (nuclei, mitochondria, synaptic membranes, and 9000 x g supernatant) showed in this respect similar sensitivities to hypoxia as indicated by the amount of protein-bound [14C]lysine in these fractions.