CCR9 and obesity due to melanocortin 4 receptor deficiency: There are no current reports on the role of Ccl4 on islet function, but the upregulation of mRNAs encoding adipose tissue Ccl4 and islet CCR1 and CCR9 in obesity suggests that increased release of Ccl4 from adipocytes in obesity could reduce insulin secretion via activation of one, or both, of these Gαi‐coupled islet receptors, exacerbating its effects to induce inflammation and insulin resistance.