ATP-dependent Ca2+ transport and Na+/Ca2+ exchange system in renal basolateral plasmamembranes of spontaneously hypertensive rats.
A common abnormality of cellular Ca2+ handling in most tissues of spontaneously hypertensive rats (SHR) has been suggested. Therefore we investigated the ATP-dependent Ca2+ transport and Na+/Ca2+ exchange system in basolateral membrane vesicles (BLMV) of renal cortices from SHR and normotensive Wistar-Kyoto rats (WKY) at 12 and 20 weeks of age. In WKY the maximal transport rate of the ATP-dependent Ca2+ transport was 5.7 nmol/min/mg prot with an affinity for Ca2+ of 0.14 microM. These values were not significantly different in SHR at both ages studied. High concentrations of Na+ inhibited ATP-dependent Ca2+ uptake by 40% in BLMV of SHR and WKY. Low concentrations of Na+ stimulated ATP-dependent Ca2+ transport 20% in both rats. These findings suggest equal Na+/Ca2+ exchange activity in WKY and SHR. The present study failed to show a significant change in ATP-dependent Ca2+ transport and Na+/Ca2+ exchange activity in renal BLMV in SHR, suggesting that the Ca2+ homeostasis of the cortical cells is normal in SHR as far as the plasmamembrane is concerned.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002132:Calcium Radioisotopes; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D006973:Hypertension / Q000201:enzymology*; D007672:Kidney Cortex / Q000201:enzymology*; D007700:Kinetics; D008297:Male; D008954:Models, Biological; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D002132:Calcium Radioisotopes; D000251:Adenosine Triphosphatases; C034688:sodium calcium ATPase; D000252:Calcium-Transporting ATPases; D002118:Calcium