Follicular mural granulosa cells stockpile glycogen to fuel corpus luteum pre-vascularization

The differentiation of follicular mural granulosa cells (fGCs) into luteal cells involves a rapid progesterone synthesis surge and the vascular network development. However, progesterone elevation occurs before vascularization, leaving luteinizing fGCs temporarily devoid of blood supply. The mechanism of how fGCs fuel increased progesterone synthesis during this avascular phase remains unclear. Our research, utilizing single-cell RNAseq and in vivo/ex vivo experiments, revealed that upon receiving the ovulatory/luteinization signal, fGCs transition to a low-energy state, reducing metabolic activity and storing glucose as glycogen. Overall design: Ovaries were collected at 0 (H0), 1 (H1), and 6 hours (H6) post-hCG injection for single-cell RNA-seq.