GIP and obesity due to melanocortin 4 receptor deficiency: In patients with obesity but without diabetes (OB+/DM−), no significant changes in longitudinal muscle contraction were observed following incubation with either GLP-1 (78.87% ± 30.47%, n = 6) or GIP (66.20% ± 22.02%, n = 6) when compared to control (84.38% ± 28.92%, n = 6; P > 0.05) (Figure 6C).