Effects of mitogenic hormones on HSP70 expression in a silver sea bream fibroblast cell line and a primary macrophage preparation

This study was performed in order to elucidate the role and importance of three mitogenic hormones [growth hormone (GH), insulin-like growth factor-I (IGF-1) and prolactin (PRL)] on heat shock protein 70 (HSP70) expression in a silver sea bream fibroblast cell line and a primary macrophage preparation. Fibroblasts and macrophages that were exposed to GH at concentrations of 1–1000 ng/ml did not exhibit modulated HSP70 expression, whereas GH at an exposure concentration of 10 ng/ml lowered HSP70 levels in macrophages. Upon exposure to IGF-1 it was found that HSP70 expression remained unchanged in fibroblasts but was significantly decreased in macrophages at exposure concentrations of 1–10 ng/ml. Finally, and using a preparation of ovine PRL it was found that HSP70 expression decreased in fibroblasts at exposure concentrations of 1–1000 ng/ml and also decreased in macrophages at exposure concentrations of 1–100 ng/ml.