Abstract
Synthetic arginine-vasotocin was infused into 1 renal portal circulation of the hen to investigate whether the antidiuretic hormone must reach the kidney cells from the blood or from the luminal side in order to produce its action. It would appear that arginine-vasotocin need not be filtered in order to have an effect since a significantly higher degree of antidiuresis (decrease in diuresis associated with increase in urine osmolality, both around 20%) was found on the side on which the infusion was made. The fact that no consistent changes in the inulin- and p-aminophippurate clearances occurred, further supports the hypothesis that the difference observed is due to a specific tubular action of the hormone.