In support of the ability to sense metabolic changes, the MHb is known to specifically express the orphan G-protein coupled receptor Gpr151, which functions to limit nicotine intake (Antolin-Fontes et al., 2020), and individuals from the UK Biobank cohort who are heterozygous for loss of function alleles of Gpr151 have decreased risk of obesity and diabetes (Emdin et al., 2018). This evidence concerns the gene GPR151 and diabetes mellitus.