Pig reticulocytes. V. Development of Rb+ influx during in vitro maturation

✍ Scribed by P. K. Lauf; R. B. Zeidler; H. D. Kim

• Book ID: 102885890
• Publisher: John Wiley and Sons
• Year: 1984
• Tongue: English
• Weight: 784 KB
• Volume: 121
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041210204

✦ Synopsis

Influx of the K + analogue Rb+ was measured through the ouabain-sensitive Na+/K+ pump and the ouabain-insensitive "leak" pathways in CI-or NO; in mature red cells from adult pigs and in reticulocytes naturally occurring in 7-day-old piglets. In reticulocytes, Rb' influxes by the two pathways were of about equal magnitude in CI-(13 and 10 mmoles/liter cells x hr) and at least 25-fold larger than in mature red cells (0.5 and 0.4 mmoles/liter cells x hr). In Na+ media, a portion of the ouabain-insensitive "leak" flux of Rb+ was CI-dependent (Rb+CI-transport) as NO, replacement reduced Rb+ influx by 90% in reticulocytes and by 40% in mature red cells. The sulfhydryl reagent N-ethylmaleimide (NEM) stimulated Rb+CI-transport about twofold in reticulocytes and up to 13-fold in mature red cells. When reticulocytes matured to erythrocytes during in vitro incubation, about 90% of both ouabain-sensitive Rb+ pump and ouabain-insensitive Rb+CI -influx were lost. In contrast, the NEM-stimulated Rb+CI-transport changed much less throughout this period, suggesting an entity operationally but not necessarily structurally distinct from t h e basal Rb+CI-transport. Although the experimental variability precluded a full assessment of significant changes in the small Na+/K+(Rb+) pump and Rb+CI-fluxes in mature pig red cells kept for the same time period in vitro, Rb+ flux changes in reticulocytes appear to be maturational in nature, reflecting parallel activity transitions of Na+/K+ pump and CI-dependent K + fluxes in vivo.