Total and active extracellular signal-regulated kinase (ERK, and pERK, respectively) protein levels were measured by immunoblot in hearts from control (C) and offspring of either moderately or severely diabetic dams (D) at 1 and 21 days of life (NB1 and NB21, respectively). In NB1 myocardial samples, ERK1 and ERK2 were both seen and quantitated as a single band. The immunoblots are shown at the top with the bar graphs indicating protein levels expressed in arbitrary units. Molecular weights: ERK1 – 42 kD, ERK2 – 44 kD, pERK – 43 kD. *p < 0.05 versus control value by unpaired t-test.