FGFR3 and myocardial ischemia: As FGF21 interacts with all known protein tyrosine kinase-coupled FGFRs, including FGFR1, FGFR2, FGFR3, and FGFR432, 36, 37, we tested the expression of these FGFRs in cardiomyocytes from wild-type mice with and without myocardial ischemia/reperfusion injury.