Isoproterenol-induced myocardial injury resulting in altered S100A4 and S100A11 protein expression in the rat

S-100 proteins (S100) are characterized by calcium-binding ability with two structural EF hands. Several S100 are expressed in cardiomyocytes and thou ght to play a crucial role in calcium signaling. To examine whether the exp ression of S100 is a response to detectable myocardial damage or regenerati on, we investigated, immunohistochemically, the expression of S100A4 and S1 00A11 in the isoproterenol (ISP)-treated rat heart. Definite expression of S100A4 and S100A11 was demonstrated in normal cardiomyocytes, and their sta ining patterns were enhanced in the ISP-treated rat heart, suggesting the p ossible involvement of S1-A4 and S100A11 in ISP-induced myocardial damage.