Cardiovascular Effects of Insulin-Like Growth Factor-1 and Growth Hormone in Chronic Left Ventricular Failure in the Rat

Abstract

IGF-1 plus growth hormone administered to rats with left ventricular failure starting 1 month after MI was associated with substantial body growth, decreased systemic vascular resistance, and increased cardiac output. The failing heart also underwent treatment-induced increases in left and right ventricular weights in proportion to body growth, but left ventricular remodeling was minor, and a decrease in the ratio of left ventricular end-diastolic volume to body weight reflected relatively less chamber dilation compared with controls. A significant interaction between size of the myocardial infarction and treatment was observed for several variables, and IGF-1 and growth hormone increased the cardia index (P < .035) in rats with a large myocardial infarction.

Endogenous production of ghrelin and beneficial effects of its exogenous administration in monocrotaline-induced pulmonary hypertension

“…Additionally, activation of the GH/IGF-1 axis increased myocardial contractility, decreased peripheral vascular resistance (1,6,8,32,38), promoted physiological myocardial hypertrophy (34), and upregulated sarco(endo)plasmic reticulum Ca 2ϩ -ATPase 2a (33) in heart failure. In the present study, RV IGF-1 mRNA levels were increased in the MCT group, which might suggest a local increase, dependent of RV overload.…”

“…Acting on hypothalamopituitary GHSR type 1a, Ghr induces a potent release of GH. Various experimental studies have shown that the GH/insulin growth factor (IGF)-1 axis improves cardiac function both in normal and failing hearts (6,8,38), although human trials revealed contradictory results about the value of GH in heart failure therapy (9,12,31).…”

Treatment With Growth Hormone Enhances Contractile Reserve and Intracellular Calcium Transients in Myocytes From Rats With Postinfarction Heart Failure

“…Duerr et al 21 administered IGF-1 plus growth hormone to rats for 4 weeks beginning 4 weeks after infarction, which stimulated body growth with minor changes in left ventricular remodeling, decreased systemic vascular resistance, and increased cardiac output compared with no treatment. Yang et al 22 administered growth hormone for 15 days to rats beginning 4 weeks after coronary ligation and observed an increase in cardiac index and dP/dt and reduction in systemic vascular resistance in the absence of an increase in the ratio of left ventricular weight to body weight.…”

Insulin-like Growth Factor-I Rapidly Activates Multiple Signal Transduction Pathways in Cultured Rat Cardiac Myocytes

“…Among growth factors, insulin-like growth factor-I (IGF-I) 1 is significant because it promotes hypertrophy by growth and differentiation in many types of cells (9 -11); it also mediates the anabolic and cardiovascular actions of growth hormone in vivo (12). IGF-I and its receptor (IGF-IR) are present on the neonatal rat myocardium, consistent with IGF-I regulating growth and hypertrophy of cardiac myocytes in the developing heart in an autocrine or paracrine manner (13).…”