CARDIAC INSULIN-LIKE GROWTH-FACTOR-I AND GROWTH-HORMONE RECEPTOR EXPRESSION IN RENAL-HYPERTENSION

The aim of the present study was to investigate the role of insulin-li ke growth factor I in the development of cardiac hypertrophy in two-ki dney, one clip hypertension by relating growth hormone receptor and in sulin-like growth factor I receptor mRNA levels to insulin-like growth factor I gene transcription using a solution hybridization/RNase prot ection assay. Two-kidney, one clip hypertension was induced in male Wi star rats, and experiments were performed 2, 4, 7, and 12 days after s urgery. Systolic blood pressure was elevated 2, 7, and 12 days after c lipping (P<.001). Left ventricular weights were increased 2, 4, 7, and 12 days after surgery (P<.01). Associated with the rise in blood pres sure, left ventricular insulin-like growth factor I mRNA was increased 2, 7, and 12 days after surgery (P<.01). Furthermore, growth hormone receptor and insulin-like growth factor I receptor gene expression inc reased specifically in the left ventricle of renal hypertensive rats ( P<.05 and P<.001, respectively). Left ventricular growth hormone recep tor mRNA peaked 7 days after induction of renal artery stenosis. These results show that insulin-like growth factor I, growth hormone recept or, and insulin-like growth factor I receptor mRNA increase in the pre ssure-overloaded left ventricle of two-kidney, one clip rats, suggesti ng a role for insulin-like growth factor I and the growth hormone/insu lin-like growth factor I axis in the development of cardiac hypertroph y.