title: Vasopressin release in response to acute hypotension induced at different time intervals in the conscious sheep.
abstract: The renal arginine vasopressin (AVP) excretion in response to acute systemic hypotension induced by intravenous infusion of sodium nitroprusside (SNP) (30-40 micrograms/kg min-1) at different experiment intervals (0, 2, 4, 7 and greater than or equal to 12 days) was studied in the conscious hyperhydrated sheep. During the first post-infusion hour, 2.5 times more AVP was excreted in response to hypotension induced at greater than or equal to 12 day intervals than that observed at intervals of 0-7 days. No interexperimental time dependence of the AVP response to SNP infusion was seen with intervals of 0-7 days. The attenuated AVP release obtained with reduced experiment intervals (0-7 days) was accompanied by shorter antidiuresis and a less accentuated natriuresis during the post-hypotensive period in comparison to what was observed with greater than or equal to 12 day experiment intervals. There were no interval-dependent differences in maximal fall of mean arterial pressure, or onset and recovery of the hypotension induced by SNP administration. It is suggested that acute systemic hypotension causes such a massive AVP release that more than one week is needed for complete restoration of a releasable neurohypophyseal pool of the hormone.
mesh_terms: D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D004231:Diuresis / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007022:Hypotension / Q000139:chemically induced / Q000503:physiopathology*; D007263:Infusions, Parenteral; D007668:Kidney / Q000378:metabolism; D009599:Nitroprusside / Q000008:administration & dosage; D012119:Respiration / Q000187:drug effects; D012756:Sheep; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D001127:Arginine Vasopressin; D009599:Nitroprusside; D012965:Sodium Chloride; D012964:Sodium