title: (Ca+Mg)ATPase and calcium influx in erythrocytes of patients with idiopathic hypercalciuria.
abstract: Increased erythrocyte (Ca+Mg)ATPase activity was previously observed in idiopathic hypercalciuria. In order to verify if this alteration is a primary or a secondary event, we studied Sr influx in erythrocytes from subjects with idiopathic hypercalciuria. (Ca+Mg)ATPase activity was significantly higher in hypercalciuric than in hypercalciuric than in normocalciuric subjects whereas no difference in Sr influx was found between the two groups. (Ca+Mg)ATPase activity positively correlated with the erythrocyte Sr content found after 5 min of incubation and with urine Ca excretion. The normal Sr permeability suggests that (Ca+Mg)ATPase is primarily altered in idiopathic hypercalciuria. The primary increase of (Ca+Mg)ATPase activity may enhance passive Ca influx by reduction of cellular Ca concentration. It may induce a defect in cellular Ca metabolism that may cause idiopathic hypercalciuria by stimulating bone Ca turn-over and enteral Ca absorption.
authors.affiliation: Department of Nephrology Dialysis and Hypertension, S. Raffaele Scientific Institute, University of Milano, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Vezzoli
authors.forename: M C
authors.initials: MC
authors.lastname: Reina
authors.forename: S
authors.initials: S
authors.lastname: Zerbi
authors.forename: R
authors.initials: R
authors.lastname: Spaventa
authors.forename: L
authors.initials: L
authors.lastname: Soldati
authors.forename: D
authors.initials: D
authors.lastname: Cusi
authors.forename: G
authors.initials: G
authors.lastname: Bianchi
mesh_terms: D001692:Biological Transport; D017301:Ca(2+) Mg(2+)-ATPase / Q000097:blood*; D002118:Calcium / Q000097:blood* / Q000652:urine*; D004912:Erythrocytes / Q000201:enzymology*; D005260:Female; D006801:Humans; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood; D013324:Strontium / Q000378:metabolism
chemical_list: D010281:Parathyroid Hormone; D010710:Phosphates; D017301:Ca(2+) Mg(2+)-ATPase; D002118:Calcium; D013324:Strontium