Regulation of cation transport pathways and glycolytic enzyme activity by alterations in red cell volume
✍ Scribed by Martha Kaloyianni; Varvara Trachana; Anna Boukla
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 174 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0263-6484
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✦ Synopsis
In the presence of NH 4 Cl and hypotonic solutions, Rana balcanica red cells respond by increasing their volume. The stimulation of cellular volume by hypotonicity is more rapid than that of NH 4 Cl, while the maximum value is less than that observed in the presence of NH 4 Cl. Depending on the cause of swelling, (net uptake of NH 4 Cl or decrease in external osmolality) cells show speci®c responses. The NH 4 Cl treatment causes a signi®cant increase in intracellular Na , from 5 . 14+0 . 78 to 29 . 84+0 . 47 mmoles l À1 cell, while hypotonicity leads to a signi®cant decrease of this cation, to 3 . 85+0 . 25 mmoles l À1 cell in relation to the control, after 30 min of incubation of Rana balcanica erythrocytes. In addition, amiloride signi®cantly reverses the NH 4 Cl eect with respect to intracellular Na . Both treatments cause a signi®cant K loss in comparison with controls. Two glycolytic enzymes glyceraldehyde phosphate dehydrogenase (GAPDH) and pyruvate kinase (PK) of Rana balcanica haemolysate were found to respond to the NH 4 Cl eect by signi®cantly decreasing their activity.