The portal blood pressure increases about 7 mm. Hg during the first forty-five seconds of peptone shock. The pressure then gradually falls, reaching normal in from eight to twelve minutes.
Perfusions of isolated livers show an increased resistance to perfusion flow as a result of the action of peptone or of peptone-blood mixtures. The resistance reaches a maximum during the second minute, and then gradually decreases, being restored to approximately normal by the tenth minute.
Mechanically increased resistance to hepatic outflow sufficient to raise the portal blood pressure 10 mm. Hg, the maximum rise during peptone shock, does not cause the hepatic-intestinal cyanosis characteristic of the peptone reaction, nor the characteristic fall in carotid blood pressure.
Theories of peptone shock based solely on the hepatic mechanical factor are, therefore, no longer tenable.