FIG. 3.

Circulating proline regulates hepatic glucose production through a central LDH-dependent mechanism. A: Schematic of pancreatic clamp procedure in rats receiving systemic infusions of proline plus either vehicle or LDH inhibitor in the MBH. B–E: Effects of the systemic administration of vehicle (n = 6, white bars), proline with central vehicle (n = 6, black bars), and proline plus central LDH inhibitor (n = 6, gray bars) on glucose infusion rate (B), glucose production (C), suppression of glucose production (D), and glucose utilization (E). *P < 0.05 vs. vehicle. All values are mean ± SEM. IV, intravenous.