IGF-I in experimental daunorubicin-induced cardiomyopathy in rabbits

1 The occurrence of IGF-I was investigated in rabbits with experimentally d aunorubicin-induced cardiomyopathy, IGF-I was measured in the heart, serum, liver and skeletal muscle. 2 A significant increase in the IGF-I was found in the left heart ventricle in daunorubicin cardiomyopathy (152.9+/-10.0 ng/g vs 95.1+/-4.2 ng/g in th e control group). This site of increased IGF-I activity corresponded well w ith the maximum of morphological changes (dispersed cytolysis of cardiomyoc ytes mostly without developed subsequent interstitial myofibrosis). 3 The highest levels of IGF-I were present in right and left cardiac atrium (but without significant differences between the groups), Furthermore, in skeletal muscle, the levels of IGF-I in the daunorubicin group (839.0+/-142 .1 ng/g) were significantly higher in comparison with the control group (48 2.5+/-83.1 ng/g). 4 The level of IGF-I in the left ventricle in the daunorubicin group (but n ot in the control group) was significantly higher than that in the liver, T here were no correlations observed between the levels of IGF-I in the heart and in the serum. 5 The increase in TGF-I concentrations in the left heart ventricle after th e administration of daunorubicin may thus reflect possible autocrine/paracr ine role of IGF-I in cardiomyopathy.