title: Osmolar stimulation of vasopressin secretion in man: comparison of various protocols.
abstract: The osmolar stimulation of vasopressin (AVP) release has been studied in 5 healthy subjects using two comparative protocols (infusion of 5% NaCl over 2 h vs 2.5% NaCl over 3 h). As AVP may be secreted by episodic bursts, AVP plasma concentrations were determined both in discrete plasma samples and in integrated samples drawn continuously by a pump over periods of 30 min. There was an earlier rise of plasma osmolality and AVP during the 5% NaCl infusion, but the final maximal value of plasma AVP did not differ in the two protocols. Plasma AVP rose from 1.3 +/- 0.7 to 3.8 +/- 1.5 during the 2.5% NaCl infusion and from 1.1 +/- 0.1 to 3.9 +/- 0.6 pg/ml during the 5% NaCl infusion. In both protocols a significant correlation obtained between the discrete and the integrated values of plasma AVP (r = 0.77 and r = 0.84 respectively, P less than 0.05). These results demonstrate that the two protocols of osmolar stimulation are equipotent in releasing AVP and do not induce episodic secretion.
mesh_terms: D000328:Adult; D001127:Arginine Vasopressin / Q000378:metabolism*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage
chemical_list: D012462:Saline Solution, Hypertonic; D001127:Arginine Vasopressin