ZONATION OF THE ACTION OF GLUCAGON ON GLUCONEOGENESIS STUDIED IN THE BIVASCULARLY PERFUSED-RAT-LIVER

We have measured the action of glucagon, infused into the hepatic artery, on gluconeogenesis from lactate in the rat liver, bivascularly perfused in both the anterograde and retrograde modes. Concerning glucose production and oxygen uptake per unit cell space, the response of the periportal cells reached via the hepatic artery in retrograde perfusion to glucagon is superior to the response of the cells reached via the same vessel in anterograde perfusion. This phenomenon, however, most probably reflects zonation of gluconeogenesis rather than zonation of the hormonal action. The latter conclusion is based on the observation that the fractional change caused by the hormone is the same for all liver cells.