Abstract: AIM: To study the effects of insulin on expression of fibronectin (FN), laminin(LN) and transforming growth factor β₁ (TGFβ₁) in cultured neonatal rat cardiac fibroblasts, and its role in induction of cardiac hypertrophy. METHODS: The neonatal rat cardiac fibroblasts were cultured and identified;the expressions of FN, LN and TGFβ₁ in experimental group (insulin treatment group) of neonatal rat cardiac fibroblasts were compared with those in control group respectively by Streptavidin- Peroxidase (SP) method. RESULTS: The cultured cells showed the characteristic of morphology and immunocytochemistry of cardiac fibroblasts;the expression of FN on the cell membrane of cardiac fibroblasts in 10^-8 mol·L ^-1 insulin treatment group increased significantly in comparison with control group (P <0.05);LN was hardly expressed on the cultured cardiac fibroblasts, and there was no difference between two groups;the expression of TGFβ1 in the cytoplasm of cardiac fibroblasts in 10^-8 mol·L ^-1 insulin treatment group increased markedly compared to the control group. CONCLUSION: Insulin can promote FN expression on cardiac fibroblasts in vitro and may be involved in the pathogenesis of cardiac hypertrophy.The promotion of insulin on the synthesis and excretion of TGFβ₁ in cardiac fibroblasts may account for this phenomena.

Key words: pharmacodynamics, insulin, fibroblast, fibronectin, laminin, transforming growth factor β₁, cardiac hypertrophy