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Pig reticulocytes. V. Development of Rb + influx during in vitro maturation
Author(s) -
Lauf P. K.,
Zeidler R. B.,
Kim H. D.
Publication year - 1984
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041210204
Subject(s) - ouabain , chemistry , in vitro , incubation , reticulocyte , microbiology and biotechnology , membrane transport , biophysics , biochemistry , sodium , biology , membrane , rna , organic chemistry , gene
Influx of the K + analogue Rb + was measured through the ouabain‐sensitive Na + /K + pump and the ouabain‐insensitive “leak” pathways in Cl − or NO − 3in 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 Cl − (13 and 10 mmoles/liter cells × hr) and at least 25‐fold larger than in mature red cells (0.5 and 0.4 mmoles/liter cells × hr). In Na + media, a portion of the ouabain‐insensitive “leak” flux of Rb + was Cl − dependent (Rb + Cl − transport) as NO − 3replacement reduced Rb + influx by 90% in reticulocytes and by 40% in mature red cells. The sulfhydryl reagent N‐ethylmaleimide (NEM) stimulated Rb + Cl − 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 + Cl − influx were lost. In contrast, the NEM‐stimulated Rb + Cl − transport changed much less throughout this period, suggesting an entity operationally but not necessarily structrually distinct from the basal Rb + Cl − transport. Although the experimental variability precluded a full assessment of significant changes in the small Na + /K + (Rb + ) pump and Rb + Cl − 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 Cl − ‐dependent K + fluxes in vivo.