Ten dogs were repeatedly subjected to barbiturate anaesthesia at different intervals. Blood samples and liver biopsy specimens were obtained during each anaesthesia. Alkaline phosphatase activity, demonstrated histochemically in the liver, in creased markedly within the first 24 hours after a barbiturate anaesthesia. The increase persisted for more than 1 week. No increase occurred in serum activity of the enzyme. Control dogs given succinylcholine and local anaesthesia showed no alkaline phosphatase increase in the liver or serum. It was assumed that the increase in alkaline phosphatase activity in the dog's liver was caused by the barbiturate and that it was induced by the effect of barbiturate on drug hydroxylating enzymes.

Arteriovenous shunting in visceral organs was studied by simultaneous injection of 15 ± 5 and 50 ± 10 (SD) µm microspheres labelled with different isotopes into the left atrium of unanesthetized, unsedated dogs, pentobarbital anesthetized dogs, unanesthetized and unsedated dogs as well as anesthetized dogs subjected to a 1-week's biliary stasis, and anesthetized dogs subjected to a 6-weeks' biliary stasis. All dogs showed moderate shunting of the smaller spheres in the stomach. Dogs subjected to a 1-week's biliary stasis demonstrated signs of shunting also in the jejunum-ileum. All anesthetized dogs, both with and without biliary obstruction, showed signs of substantial shunting outside the visceral area. In dogs subjected to a 1-week's biliary stasis the liver blood flow was increased owing to increased flow through the hepatic artery.

A new technique for selective catheterization of the common and proper hepatic arteries in dogs is described. Using this technique the disappearance rate of 133Xe from they liver after administration of the isotope in the coeliac, the common hepatic and the proper hepatic arteries was studied. From the obtained results it was concluded that when measuring liver blood flow after arterial administration of the tracer substance a selective administration of the isotope in the common artery is preferable.