A novel subset of hepatocytes is simultaneously gluconeogenic and <i>de novo</i> lipogenic in the fed state and is naturally insulin resistant

It is generally accepted that hepatic gluconeogenesis, the synthesis of glucose from non-carbohydrate substrates is active in the fasted state and inactive in the fed state. In contrast, <i>de novo</i> lipogenesis is active in the fed state and is inactive in the fasted state. Here, we used targeted single cell RNA-seq, HCR RNA-FISH, and PrimeFlow in normal physiological mouse liver, and identified a subpopulation of periportal hepatocytes that simultaneously co-express both gluconeogenic and lipogenic genes in the fed state. Euglycemic-hyperinsulinemic clamps further demonstrated that this novel hepatocyte subpopulation is naturally insulin resistant. Spatial metabolic imaging coupled with stable isotope tracing analyses revealed individual hepatocytes that simultaneously undergo both gluconeogenesis and <i>de novo</i> lipogenesis. These dual-positive hepatocytes were also present in human hepatocytes from humanized mouse livers. Moreover, the number of dual-positive hepatocytes increased in high-fat diet-fed mice, suggesting a paradigm shift in our understanding of how the liver becomes insulin resistant.