Hepatocyte metabolic adaptations during pregnancy and lactation

The liver undergoes metabolic adaptations during gestation and lactation to meet evolving physiological demands, yet the precise processes, regulatory mechanisms, and functions remain unclear. Using high-resolution single-cell RNA sequencing, we systematically characterized hepatocyte adaptations in mice across pregnancy and postpartum stages. We discovered a cyclical hepatocyte trajectory ("pregnancy clock") that governs metabolic changes during gestation and postpartum recovery, reverting to pregestational states in non-lactating mice. Lactation induced a distinct branching trajectory characterized by elevated lipid synthesis and export. Deletion of glycoprotein 130 (gp130) disrupted hepatic adaptations during pregnancy, impairing fetal growth, whereas acetyl-coenzyme A (CoA) synthetase 2 (ACSS2) deficiency postpartum impaired hepatic lipid biosynthesis and export, reducing milk lipid content and compromising offspring development. Comparative analysis with sheep highlighted conserved hepatic metabolic adaptation pathways despite genetic divergence between species. These insights clarify hepatocyte plasticity during pregnancy and lactation, identifying potential therapeutic targets to optimize maternal-fetal health and lactation performance, with implications for reproductive biology and livestock management.