Regulation of cation transport pathways and glycolytic enzyme activity by alterations in red cell volume.
In the presence of NH4Cl 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 NH4Cl, while the maximum value is less than that observed in the presence of NH4Cl. Depending on the cause of swelling, (nct uptake of NH4Cl or decrease in external osmolality) cells show specific responses. The NH4Cl treatment causes a significant increase in intracellular Na+, from 5.14 +/- 0.78 to 29.84 +/- 0.47 mmoles l-1 cell, while hypotonicity leads to a significant decrease of this cation, to 3.85 +/- 0.25 mmoles l-1 cell in relation to the control, after 30 min of incubation of Rana balcanica erythrocytes. In addition, amiloiride significantly reverses the NH4Cl effect with respect to intracellular Na+. Both treatments cause a significant 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 NH4Cl effect by significantly decreasing their activity.
Kaloyianni
M
M
Zoology Department, School of Biology, Aristotle University of Thessaloniki, Greece.
Trachana
V
V
Boukla
A
A
D000584:Amiloride / Q000494:pharmacology; D000643:Ammonium Chloride / Q000494:pharmacology*; D000818:Animals; D001692:Biological Transport; D002412:Cations / Q000493:pharmacokinetics*; D004911:Erythrocyte Volume / Q000187:drug effects*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000097:blood / Q000187:drug effects*; D006019:Glycolysis / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D007038:Hypotonic Solutions; D009997:Osmotic Pressure; D011770:Pyruvate Kinase / Q000097:blood / Q000187:drug effects*; D011898:Ranidae
D002412:Cations; D007038:Hypotonic Solutions; D000643:Ammonium Chloride; D000584:Amiloride; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D011770:Pyruvate Kinase