SELECTIVE INCREASE IN CARDIAC IGF-1 IN A RAT MODEL OF VENTRICULAR HYPERTROPHY

There is evidence that insulin-like growth factor-1 (IGF-1) plays a ro le in the development of left ventricular hypertrophy, but it is uncer tain whether cardiac IGF-1 changes before or after hypertension is est ablished, and whether circulating IGF-1 are involved in cardiac hypert rophy. We have investigated changes in circulating and left ventricula r IGF-1 and in the expression of the IGF-1 gene in the left ventricles of rats during the development of hypertensive left ventricular hyper trophy (Goldblatt model; 2 kidney-1 clamped). Our results show that th e left ventricular contents of IGF-1 and its mRNA mere increased at on e and four weeks of hypertension and hypertrophy, and that both return ed to control values after nine weeks. These changes were unrelated to the seric concentration of IGF-1 in the blood. These results show tha t local rather than circulating IGF-1 levels contributed to the develo pment of renovascular hypertensive left ventricular hypertrophy. (C) 1 998 Academic Press.