title: Pharmacologic atrial natriuretic peptide reduces human leg capillary filtration.
abstract: Atrial natriuretic peptide (ANP) is produced and secreted by atrial cells. We measured calf capillary filtration rate with prolonged venous-occlusion plethysmography of supine healthy male subjects during pharmacologic infusion of ANP (48 pmol/kg/min for 15 min; n = 6) and during placebo infusion (n = 7). Results during infusions were compared to prior control measurements. ANP infusion increased plasma [ANP] from 30 +/- 4 to 2,568 +/- 595 pmol/l. Systemic hemoconcentration occurred during ANP infusion: mean hematocrit and plasma colloid osmotic pressure increased 4.6 and 11.3%, respectively, relative to preinfusion baseline values (p < 0.05). Mean calf filtration, however, was significantly reduced from 0.15 to 0.08 ml/100 ml/min with ANP. Heart rate increased 20% with ANP infusion, whereas blood pressure was unchanged. Calf conductance (blood flow/arterial pressure) and venous compliance were unaffected by ANP infusion. Placebo infusion had no effect relative to prior baseline control measurements. Although ANP induced systemic capillary filtration, in the calf, filtration was reduced with ANP. Therefore, pharmacologic ANP infusion enhances capillary filtration from the systemic circulation, perhaps at upper body or splanchnic sites or both, while having the opposite effect in the leg.
authors.affiliation: University of Texas Southwestern Medical Center, Dallas, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Watenpaugh
authors.forename: S F
authors.initials: SF
authors.lastname: Vissing
authors.forename: L D
authors.initials: LD
authors.lastname: Lane
authors.forename: J C
authors.initials: JC
authors.lastname: Buckey
authors.forename: B G
authors.initials: BG
authors.lastname: Firth
authors.forename: W
authors.initials: W
authors.lastname: Erdman
authors.forename: A R
authors.initials: AR
authors.lastname: Hargens
authors.forename: C G
authors.initials: CG
authors.lastname: Blomqvist
mesh_terms: D000328:Adult; D009320:Atrial Natriuretic Factor / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000187:drug effects; D002199:Capillary Permeability / Q000187:drug effects*; D004562:Electrocardiography / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006400:Hematocrit; D006801:Humans; D007866:Leg / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D010991:Plethysmography; D012016:Reference Values; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D009320:Atrial Natriuretic Factor