Adrenomedullin gene expression and peptide levels in the heart and blood vessels of streptozotocin-diabetic rats.
The aim of the present study was to assess the changes in gene expression and peptide adrenomedullin (AM) levels in cardiovascular and other tissues in the streptozotocin-diabetic rats. For this purpose, diabetes was induced by intraperitoneal injection of streptozotocin (STZ, 65 mg/Kg body weight). Half of the diabetic rats were subcutaneously injected with insulin in the afternoon (4 units/day) one week after STZ injection until the day before killing. Control rats received only saline injection. AM mRNA was determined in cardiovascular and other tissues of streptozotocin-diabetic rats using solution-hybridization-RNase protection assay. Circulating AM and peptide AM in cardiovascular and other tissues were estimated using a specific radioimmunoassay. There were increases in preproAM mRNA levels in the left and right ventricles and in the thoracic aorta in both the 2-week and 4-week diabetic rats, but not in the two atria, the mesenteric artery and the lung. In the 2-week diabetic rats, there were decreases in AM contents in the two atria and the lung but an increase in the thoracic aorta. In the 4-week diabetic rats, there were bigger decreases in the atria and also a decrease in the left ventricle. The plasma AM levels were not changed but there was an increase in the excretion of AM in the urine. Our results suggest a possible increase in AM release in the heart and the thoracic aorta in the 2-week and 4-week diabetic rats.
Tang
F
F
Department of Physiology and Centre of Heart, Brain, Hormones and Healthy Aging, Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, China. ftang@hkucc.hku.hk
Hwang
I S S
IS
Wong
M P F
MP
Li
Y-Y
YY
D053607:Adrenomedullin / Q000097:blood / Q000235:genetics / Q000378:metabolism* / Q000652:urine; D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism; D001808:Blood Vessels / Q000737:chemistry / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000378:metabolism* / Q000652:urine; D006352:Heart Ventricles / Q000378:metabolism; D008297:Male; D008638:Mesenteric Arteries / Q000378:metabolism; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism*; D010455:Peptides / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013311:Streptozocin
D010455:Peptides; D053607:Adrenomedullin; D013311:Streptozocin