title: The cardiovascular and renal effects of hydrins and arginine vasotocin in frogs.
abstract: Cardiovascular and renal actions of hydrins and arginine vasotocin (AVT) in frogs (Rana tigrina and Rana catesbeiana) were examined in view of their relationships as precursor/prohormone-hormones in the anuran amphibian. In vitro hydrins and AVT respectively vasorelaxed and vasoconstricted KCl-preconstricted femoral artery in R. tigrina. AVT also produced dose-dependent contractions on untreated preparations; hydrins had no effect on these preparations. Both the hydrins and AVT were positively inotropic and chronotropic, with AVT being more potent. In vivo hydrins and AVT were anti-diuretic except at high doses, when AVT became diuretic. The hydrins and AVT were vasodepressor and pressor, respectively, in R. catesbeiana. These data suggest that the addition of one to three amino acids onto the AVT molecule reverses the contractile response in the vascular smooth muscle. With this dissociation of the vascular effect from that of the renal, the hydrins might play a physiological role in water balance of frogs.
authors.affiliation: Department of Biology, Chinese University of Hong Kong.
authors.forename: K W
authors.initials: KW
authors.lastname: Chiu
authors.forename: Y C
authors.initials: YC
authors.lastname: Lee
authors.forename: P K
authors.initials: PK
authors.lastname: Pang
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002320:Cardiovascular Physiological Phenomena; D002319:Cardiovascular System / Q000187:drug effects*; D004231:Diuresis / Q000187:drug effects; D005260:Female; D005263:Femoral Artery / Q000187:drug effects / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects; D007668:Kidney / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D011189:Potassium Chloride / Q000494:pharmacology; D011892:Rana catesbeiana / Q000502:physiology*; D011898:Ranidae / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects; D014668:Vasotocin / Q000031:analogs & derivatives* / Q000494:pharmacology*
chemical_list: C060257:hydrin 1; C060258:hydrin 2; D011189:Potassium Chloride; D014668:Vasotocin