Figure 1: Adult rat cardiomyocytes express and secrete FGF23. Adult rat cardiomyocytes were treated with 20 ng/ml albumin (Con), 20 ng/ml of oncostatin M (OSM) or leukemia inhibitory factor (LIF). (A) Analysis of FGF23 mRNA expression in cultured adult cardiomyocytes after 7d in % of control and FGF23 ELISA (C-terminal) of the supernatant of the same cultures. (B) Cell lysates from day 14 were applied to Western Blot analysis. (C) Supernatants of cultured adult cardiomyocytes were collected from day 7 to 12, were concentrated (supernatant) and applied to Western Blot analysis. Note the unspecific band of the cell lysate in (B) which is marked by a grey triangle.