HTR2C and obesity due to melanocortin 4 receptor deficiency: By contrast, 17 of the enriched cell types expressed the serotonin receptor 5-Htr2c (5-hydroxytryptamine receptor 2C), a known regulator of energy and glucose homeostasis (Berglund et al., 2013) and a target for anti-obesity pharmacotherapy (Halford et al., 2011; Figure 6b).