TGFB1 and obesity due to melanocortin 4 receptor deficiency: Interestingly, Exd-4 reduced TGF-β1 expression in the chow-fed but not HFD-fed offspring of the obese mothers (p < 0.05, Fig. 4B), suggesting that diet-induced obesity in postnatal life outweighs the beneficial effect of Exd-4 therapy on TGF-β1 levels.