TGFB3 and obesity due to melanocortin 4 receptor deficiency: Consistent with published studies [34, 35], obesity increased cardiac mRNA abundance of several fibrosis-related genes, including Map 3k7, Tgfb3, Tgfbr2, Tgfbr3, and Smad2. Despite the marked increase in LV mass, mRNA abundance of profibrotic genes was not proportionally increased in obese postpartum female mice, and there was no difference in LV interstitial collagen content in obese postpartum compared with nulliparous mice.