title: Calcium and sodium handling during volume expansion in essential hypertension.
abstract: To evaluate the actual role of extracellular fluid volume (ECFV) expansion per se in modulating the rate of urinary calcium excretion, a thermoneutral water immersion (WI) study was conducted in 10 normal subjects and 30 patients with essential hypertension. Central hypervolemia by 2 hours of WI caused a significant diuretic and natriuretic response (P < .005) in normal subjects; no significant changes were detected in urinary calcium and magnesium excretion. WI provoked either an appropriate or exaggerated natriuresis (P < .001) in 21 hypertensive patients; these subjects also exhibited a highly positive correlation between urinary sodium and calcium excretion during WI (P < .001). In the remaining nine hypertensive patients, WI produced a significant diuretic response, but a barely discernible (P = NS) natriuresis (inappropriate response). These subjects also exhibited a significant reduction of urinary calcium (P < .001) and magnesium (P < .01) excretion. The data indicate that (1) volume expansion per se may have a role in regulating calcium excretion in hypertensive subjects; (2) a calcium leak may be attributable to a close relationship between urinary sodium and calcium metabolism, and causally related to a disturbance of sodium and volume homeostasis in hypertension.
authors.affiliation: Institute of Semeiotica Medica, University of Parma, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Coruzzi
authors.forename: A
authors.initials: A
authors.lastname: Biggi
authors.forename: L
authors.initials: L
authors.lastname: Musiari
authors.forename: R
authors.initials: R
authors.lastname: Ceriati
authors.forename: G L
authors.initials: GL
authors.lastname: Mossini
authors.forename: A
authors.initials: A
authors.lastname: Guerra
authors.forename: A
authors.initials: A
authors.lastname: Novarini
mesh_terms: D000328:Adult; D002118:Calcium / Q000652:urine*; D005110:Extracellular Space / Q000502:physiology; D005260:Female; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology / Q000652:urine*; D008274:Magnesium / Q000652:urine; D008297:Male; D008875:Middle Aged; D012964:Sodium / Q000652:urine*
chemical_list: D012964:Sodium; D008274:Magnesium; D002118:Calcium