GIP and obesity due to melanocortin 4 receptor deficiency: Further research performed by this research team demonstrated that, in mice, GIPR is expressed in BAT, and GIP directly increases interleukin-6 (IL-6) mRNA and IL-6 secretion in BAT cells; however, the loss of the GIPR signaling within BAT alone was not associated with decreased weight gain and resistance to obesity [89].