Angiotensins promote fluid absorption in the rat ileum after their CNS administration.
Angiotensin II (A-II) has been found previously to increase mean arterial pressure (MAP) and enhance fluid absorption in the rat ileum in situ after intracerebroventricular (ICV) administration. In this investigation, the CNS-mediated proabsorptive actions of A-II and other products of the renin-angiotensin system, as well as nonhomologous peptides were further characterized in the urethane-anesthetized rat. At an ICV bolus dose of 1 microgram, angiotensinogen, A-I, A-II and A-III produced significant elevations in MAP, but only A-II and A-III increased ileal absorption significantly above that of saline-treated rats. The ICV administration of other unrelated peptides did not mimic the actions of A-II or A-III. The results suggest that the pressor and ileal proabsorptive actions of angiotensins are mediated through different CNS mechanisms and that these peptides uniquely alter intestinal transport.
Brown
D R
DR
Department of Veterinary Biology, University of Minnesota, College of Veterinary Medicine, St. Paul 55108.
Gillespie
M A
MA
D000803:Angiotensin I / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000805:Angiotensin III / Q000494:pharmacology; D000808:Angiotensinogen / Q000494:pharmacology; D000809:Angiotensins / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D007082:Ileum / Q000187:drug effects / Q000502:physiology*; D007276:Injections, Intraventricular; D007408:Intestinal Absorption / Q000187:drug effects; D008297:Male; D011092:Polyethylene Glycols; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
D000809:Angiotensins; D000808:Angiotensinogen; D000804:Angiotensin II; D000805:Angiotensin III; D011092:Polyethylene Glycols; D000803:Angiotensin I