Upregulation of GLUT-4 in right ventricle of rats with monocrotaline-induced pulmonary hypertension.
BACKGROUND
Pulmonary hypertension is characterized by abnormal vascular remodeling leading to occlusion of pulmonary arteries and increased stress placed on the right ventricle (RV). This causes the RV to hypertrophy and eventually to failure. This study was designed to examine the effects of pulmonary hypertension in rats on right ventricular remodeling and glucose transporter protein (GLUT4) content in right (RV) and left ventricle (LV).


METHODS
Pulmonary hypertension was induced in male Sprague-Dawley rat by a single subcutaneous injection of monocrotaline (MCT) at the concentration of 60 mg/kg. Forty-six days following the injection of MCT, animals were sacrificed.


RESULTS
MCT-treated rats displayed significant increases in lung weight and RV weight. Marked RV hypertrophy was evident as the ratio of the RV to LV plus septum weight was nearly 40% higher in MCT-treated rats compared to control rats. Total GLUT4 content from whole homogenates from the RV was increased by approximately 28% in MCT-treated hearts compared to control hearts. No differences, however, in the LV content between groups were observed.


CONCLUSIONS
Our findings indicate that the structural remodeling of the RV in MCT-induced pulmonary hypertension results in the upregulation of glucose transporters. This increase in RV GLUT4 levels may potentially result in alterations in substrate energy metabolism.
Broderick
Tom L
TL
Laboratory of Diabetes and Exercise Metabolism, Department of Physiology, Midwestern University, Glendale, AZ 85308, USA. tbrode@midwestern.edu
King
Tiffany M
TM
D000818:Animals; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D006352:Heart Ventricles / Q000378:metabolism* / Q000503:physiopathology; D006976:Hypertension, Pulmonary / Q000139:chemically induced / Q000378:metabolism*; D008297:Male; D016686:Monocrotaline / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation
D051275:Glucose Transporter Type 4; D016686:Monocrotaline