What is the role of intestinal citrulline production in protein homeostasis?

Abstract

Rationale: Plasma citrulline (Cit) is mainly determined by the balance between its production by the gut and its renal conversion to arginine (Arg). Enterocytes, like hepatocytes, express ornithine carbamyl transferase (OCT), that converts ornithine (Orn) to Cit. As our studies demonstrate that pharmacological doses of Cit activate muscle protein synthesis, we questioned whether intestinal OCT may be a major effector of muscle homeostasis. Since neonatal OCT deficiency is associated with early lethality, this was addressed in a model of conditional intestinal OCT invalidation enabling to specifically suppress OCT intestinal expression in adult mice.