TPH1 and fatty liver disease: Specifically, in CDAA, HFD and MC4RKO+HFD models, the expression of genes involved in fatty acid synthesis, such as Acaca, Fasn and Gpat1 (also known as Gpam), remained suppressed up to 4 weeks after visceral nerve blockade, but recovered by 8 weeks (Fig. 4), which is consistent with changes in hepatic steatosis, 5-HT and Tph1 expression (Figs 1 and 2), due to the recovery from capsaicin-induced nerve blockade (Ko et al., 2021).