Biochemical changes during reticulocyte maturation in culture. A comparison of genetically different sheep erythrocytes.

A simple culture technique was used to follow sheep reticulocyte maturation. Cells remained in good condition without lysis for at least 7 days and maintained normal intracellular ATP concentrations. Amino acid and nucleoside transport were measured during maturation together with changes in reduced glutathione (GSH), amino acid, K+ and Na+ concentrations. Reticulocytes of the genetic types high-K+ and low-K+, high-GSH and low-GSH; nucleoside-permeable and nucleoside-impermeable were indistinguishable both in transport properties and cellular constituents. Cell maturation was associated with marked decreases in L-alanine transport (Na+-dependent and independent), uridine transport and GSH and K+ concentrations. Typical mature-cell levels for all parameters were reached within the culture period, during which time predicted differences between cells of different genotypes became apparent. Loss of amino acid-transport activity from low-GSH cells was accompanied by an increase in intracellular ornithine and lysine concentrations. The rates at which different parameters changed during culture were compared.