title: Age-dependent cardiovascular, renal and endocrine responses to furosemide in conscious lambs.
abstract: 1. The present study was performed to investigate some of the physiological responses to furosemide during postnatal maturation. 2. In 1- (n = 8) and 6-week old (n = 10) conscious, chronically instrumented lambs at least 3 days after surgery, three experiments were performed at intervals of 24-48 h and in random order. Various parameters of cardiovascular and endocrine function, as well as cumulative urinary flow rates, were measured before and after intravenous injection of 0 mg/kg (experiment one), 0.25 mg/kg (experiment two; low dose) and 5 mg/kg (experiment three; high dose) furosemide. 3. After high-dose furosemide, mean venous pressure decreased and there was a transient increase in mean arterial pressure in lambs aged 6 weeks. At 1 week of age, heart rate increased after high-dose furosemide and renal blood flow decreased. After high-dose furosemide, plasma renin activity increased in both groups of lambs, although the effects were greater in 1-week-old lambs. Plasma levels of arginine vasopressin increased after high-dose furosemide in lambs aged 1 but not 6 weeks. Cumulative urinary flow rate responses to furosemide were similar in 1- and 6-week-old lambs. 4. These data provide new information that cardiovascular and endocrine responses to furosemide are developmentally regulated.
authors.affiliation: Department of Physiology and Biophysics/Medicine, Faculty of Medicine, University of Calgary, 330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada.
authors.forename: Julie J
authors.initials: JJ
authors.lastname: Thomson
authors.forename: Francine G
authors.initials: FG
authors.lastname: Smith
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood; D001798:Blood Proteins / Q000378:metabolism; D004232:Diuretics / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004703:Endocrine System / Q000187:drug effects*; D005665:Furosemide / Q000494:pharmacology*; D006400:Hematocrit; D006439:Hemodynamics / Q000187:drug effects*; D007275:Injections, Intravenous; D007668:Kidney / Q000187:drug effects*; D012079:Renal Circulation / Q000187:drug effects; D012083:Renin / Q000097:blood; D012756:Sheep; D014563:Urodynamics / Q000187:drug effects
chemical_list: D001798:Blood Proteins; D004232:Diuretics; D001127:Arginine Vasopressin; D005665:Furosemide; D012083:Renin