Hepatic osmoreceptors?

1. The effects of 0.45% saline infusions into the portal vein of conscious and anaesthetized dogs have been compared with similar infusions through a systemic vein.2. Measurements were made of plasma and urinary osmolality, sodium, potassium and chloride concentrations and urine flows; osmolal clearances, free water clearances, the percentage of the infused loads excreted at given times, and rates of sodium and potassium excretion in the urine, were calculated.3. In the conscious and anaesthetized series of experiments no significant differences were found between the portal and systemic routes of infusion.4. For both the portal and systemic routes of infusion there was a significantly smaller diuretic response to the saline infusion in anaesthetized as compared with conscious animals.5. These results do not support the concept of hepatic osmoreceptors occurring in the dog.