Résumé
In this paper we report the erythrocyte sodium concentration and Na+, K(+)-ATPase activity in 86 untreated hypertensives and their 77 first degree relatives and also in sex and age matched controls. There was significant increase in erythrocyte sodium both in the hypertensives and their first degree relatives (p < 0.01), whereas Na+, K(+)-ATPase activity was significantly reduced in the study group when compared with controls. The possibility of using these parameters as genetic markers is suggested.
Sujets)
Pression sanguine , Érythrocytes/enzymologie , Femelle , Humains , Hypertension artérielle/métabolisme , Liquide intracellulaire/métabolisme , Mâle , Sodium/métabolisme , Sodium-Potassium-Exchanging ATPase/métabolismeRésumé
To study the mechanism of haemolysis in G6PD deficient erythrocytes, studies were undertaken in G6PD deficiency and in normal erythrocytes artificially loaded with calcium. Significantly increased concentrations of calcium, calcium activated neutral protease (CANP) and calcium ATPase were found in patients of G6PD deficiency. However, the membrane bound calcium, the total glycoprotein and sulphydryl groups of membrane were observed to be decreased. Similar results were also observed in the normal erythrocytes when loaded with calcium. These results point to the role of the proteolytic process in membrane modification, and altered membrane permeability during the haemolytic process. Our observations in G6PD deficiency and in in vitro point to the existence of a calcium dependent proteolytic preconditioning of erythrocyte accelerating the haemolysis.
Sujets)
Adulte , Calcium/pharmacologie , Calcium-Transporting ATPases/effets des médicaments et des substances chimiques , Enfant , Enfant d'âge préscolaire , Endopeptidases/effets des médicaments et des substances chimiques , Activation enzymatique , Femelle , Déficit en glucose-6-phosphate-déshydrogénase/enzymologie , Humains , Nourrisson , Mâle , MutationRésumé
Increase in cytosolic calcium leads to activation of calcium activated neutral protease (CANP). CANP is known to cause many membrane abnormalities that aid erythrocyte destruction. An epoxy compound Ep475 causes the reversal of such changes induced by calcium and CANP. In absence of Ep475, CANP caused reduction in free sulfhydryl groups and glycoprotein content of the membrane to 61, and 50% respectively, compared to untreated membranes. Calcium ATPase and membrane associated CANP were increased 3 and 1.4 times respectively. Significant reversal of these changes by Ep475 suggests a possible role of this compound in reversing the calcium dependent alterations in RBC including the action of CANP.