Ouabain binding and potassium transport in young and old populations of human red cells
Joiner, CH; Lauf, PK
| HERO ID | 1599003 |
|---|---|
| In Press | No |
| Year | 1978 |
| Title | Ouabain binding and potassium transport in young and old populations of human red cells |
| Authors | Joiner, CH; Lauf, PK |
| Volume | 1 |
| Issue | 3-4 |
| Page Numbers | 187-202 |
| Abstract | Human red blood cells were separated according to density by centrifugation through mixtures of phthalate esters. The densest 20% of the erythrocyte population (old cells) had reduced volume and water content compared to the lightest 20% of the cells (young cells). Corpuscular hemoglobin content was unchanged. Young cells had 50% more potassium (K+) than old cells, but their total intracellular concentration was only slightly higher, old cells had a small increase in sodium (Na+) concentration. Active K+ transport of young cells was 37% higher than that of old cells. [3H] + Ouabain binding revealed that this difference was the result of more K+ pump sites on young cells, which bound 530 ouabain molecules per cell at 100% K+ pump inhibition, as compared to 400 for old cells; unseparated cells bound 450-500 molecules. The relative rates of ouabain binding were identical for the two cell types. Old cells exhibited a greater passive permeability to K+, having a rate coefficient for ouabain-insensitive K+ influx 1.8 times that of young cells. There is evidence to suggest that in the face of reduced pump activity this augmented K+ "leak" might enhance the osmotic stability of the old cells and function to lengthen their life span. |
| Pmid | 756487 |
| Is Certified Translation | No |
| Dupe Override | No |
| Comments | Journal: Membrane biochemistry ISSN: 0149-046X |
| Is Public | Yes |
| Language Text | English |