title: Abnormal erythrocyte and renal frusemide-sensitive sodium transport in idiopathic calcium nephrolithiasis.
abstract: 1. Anomalous transmembrane anion transport has been observed in erythrocytes of patients with idiopathic calcium nephrolithiasis. 2. To verify whether cation transport is also abnormal, we investigated the frusemide-sensitive Na+ efflux from Na(+)-loaded erythrocytes and the natriuretic response to acute intravenous frusemide administration in calcium oxalate renal stone formers. 3. Frusemide administration induced a statistically significant smaller increase in the fractional excretion of Na+ in patients than in control subjects. Abnormal kinetic properties of erythrocyte Na(+)-K(+)-2Cl- cotransport were observed in approximately 60% of stone formers. The Km for Na+ of Na(+)-K(+)-2Cl- co-transport correlated with urinary Ca2+ excretion. 4. The abnormal kinetic properties of Na(+)-K(+)-2Cl- co-transport may be relevant for stone formation, hampering renal Ca2+ reabsorption in the distal nephron and determining critical physicochemical conditions for calcium/oxalate crystallization.
authors.affiliation: Division of Nephrology, Policlinico Universitario, Padova, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Baggio
authors.forename: G
authors.initials: G
authors.lastname: Gambaro
authors.forename: F
authors.initials: F
authors.lastname: Marchini
authors.forename: M
authors.initials: M
authors.lastname: Vincenti
authors.forename: G
authors.initials: G
authors.lastname: Ceolotto
authors.forename: A C
authors.initials: AC
authors.lastname: Pessina
authors.forename: A
authors.initials: A
authors.lastname: Semplicini
mesh_terms: D000328:Adult; D001693:Biological Transport, Active; D002712:Chlorides / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D005665:Furosemide; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009397:Nephrocalcinosis / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*
chemical_list: D002712:Chlorides; D005665:Furosemide; D012964:Sodium; D011188:Potassium