abstract
- Distribution of basic-fibroblast-growth-factor-like peptides in immature cultured cardiac myocytes was investigated using specific antisera and immunolocalization. Basic FGF was detected in association with the external surface of the cell membrane, with specialized intercellular junctions and with the myofibril Z lines in the cytoplasm. Intense, punctate nuclear anti-bFGF labeling was observed in a fraction of interphase myocytes of near-confluent, proliferating cultures. This staining pattern persisted even after the dissolution of the nuclear envelope in prophase myocytes. The pattern of cellular localization of bFGF indicates a continuous participation of this factor in myocyte physiology as well as a role in the cell cycle. Furthermore, the identification of bFGF not only in cell lysates but also in culture media after gentle mechanical disruption suggests that cardiac myocytes may release bFGF in vivo following tissue damage.