title: Orally administered L-arginine does not alter right ventricular hypertrophy in chronically hypoxic rats.
abstract: Evidence suggests that nitric oxide synthesis within the pulmonary circulation may be attenuated during chronic hypoxia in Wistar rats due to reduced L-arginine availability. In contrast, chronically hypoxic Sprague-Dawley rats exhibit normal endothelium-dependent pulmonary vasodilation. The purpose of the present study was to determine whether 1) Wistar rats demonstrate greater right ventricular (RV) hypertrophy in response to chronic hypoxia than Sprague-Dawley rats and 2) chronic administration of L-arginine would diminish this response in Wistar rats. L-Arginine had no effect on the degree of hypoxia-induced RV hypertrophy or polycythemia in either strain of rat. However, Wistar rats demonstrated greater hypoxia-induced RV hypertrophy and polycythemia compared with Sprague-Dawley rats. To determine whether chronically hypoxic Wistar rats indeed exhibit impaired endothelium-dependent pulmonary vasodilation, isolated lungs from control and chronically hypoxic Wistar rats were administered the endothelium-dependent pulmonary vasodilators A23187 or vasopressin. Vasodilatory responses to either agent were unaffected by chronic hypoxic exposure. We conclude that endothelium-dependent pulmonary vasodilation is maintained in the pulmonary circulation of chronically hypoxic Wistar and Sprague-Dawley rats.
authors.affiliation: Department of Physiology, University of New Mexico School of Medicine, Albuquerque 87131.
authors.forename: T C
authors.initials: TC
authors.lastname: Resta
authors.forename: B R
authors.initials: BR
authors.lastname: Walker
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D006352:Heart Ventricles; D017380:Hypertrophy, Right Ventricular / Q000209:etiology / Q000503:physiopathology*; D000860:Hypoxia / Q000503:physiopathology*; D007536:Isomerism; D011086:Polycythemia / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D013045:Species Specificity
chemical_list: D001120:Arginine