[Urinary excretion of kallikrein and sensitivity of blood pressure to acute sodium loading in healthy subjects].

Acute extracellular volume expansion (VE) by isotonic saline is associated with variable change in mean arterial pressure (MAP) in normotensive subjects (NT). Following VE by 1,800 ml isotonic saline in 3 h, two patterns of MAP response were observed in NT: either an increase by more than 10% (SS: sodium or VE sensitive, n = 12) or no change (NSS: non-sodium or VE sensitive, n = 14). We assessed in all subjects the response to VE of glomerular filtration rate (GFR), urinary sodium (UNaV) and kallikrein (UKalV) excretion rate, plasma renin activity (PRA) and aldosterone concentration (PAC). Family history of blood pressure was not different between the groups. In response to VE, MAP increased (88 +/- 3 to 102 +/- 4 mmHg) in group SS and did not change in group NSS (83 +/- 3 to 85 +/- 3 mmHg). Whilst UNaV measured during the hour prior to VE was similar in both groups, the total amount of sodium excreted during VE was higher in group SS than in group NSS (52 +/- 9 vs 32 +/- 3 mmol/3 h, p less than 0.05). Control GFR as well as changes in GFR associated with VE were similar in both groups. A similar decrease in PRA and PAC was observed in both groups and pre-VE values were identical. UKalV was lower in SS than NSS subjects during the pre-VE control jour (0.42 +/- 0.09 vs 0.74 nKat/h; p less than 0.05) and during VE (1.14 +/- 0.16 vs 2.5 vs 0.47 nKat/3 h; p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)