NRG1 and hydrops fetalis: Using a rat model of HF due to MI by coronary ligation in the presence of STZ-induced DM, a type 1 model, we assessed the protein expression profiles of NRG-1β, ErbB2 and ErbB4 receptors, MDM2 (a downstream signaling pathway induced by NRG-1 that has been implicated in cell survival), as well as changes in ErbB receptor localization in the surviving LV myocardium of diabetic post-MI rats in relation to residual LV function.