Calcium and sodium permeability of human reticulocytes have been studied and compared to mature erythrocytes. Mature erythrocytes had extremely low Ca2+ permeability which was less than 0.1% of values published for squid axon or HeLa cells. Calcium entry was markedly increased in reticulocyte-rich suspensions and the uptake was linearly related to the percentage of reticulocytes present. The data suggest that reticulocytes are 43-fold more permeable to Ca2+ than mature cells although their Ca2+ concentration is not increased. Sodium influx into reticulocyte-rich suspensions was also increased in direct proportion to the percent of reticulocytes present. Reticulocytes are sixfold more permeable to Na+ than mature cells so the ratio of Ca2+:Na+ permeability falls by sevenfold as the reticulocyte changes to an erythrocyte. [3H]Ouabain binding was increased in reticulocyte-rich cell suspensions and the correlation suggested a value of about 4,000 sites per reticulocyte compared with 362+/-69 per mature cell. Maturation of the human reticulocyte produces disproportionate changes in cation permeability and in particular a selective loss of Ca2+ permeability.
J S Wiley, C C Shaller
Usage data is cumulative from May 2023 through May 2024.
Usage | JCI | PMC |
---|---|---|
Text version | 68 | 0 |
53 | 13 | |
Scanned page | 55 | 0 |
Citation downloads | 11 | 0 |
Totals | 187 | 13 |
Total Views | 200 |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.