Effects of norepinephrine on the action of antidiuretic hormone in the dog kidney

In general norepinephrine (NE) exhibits antagonistic effects to that of antidiuretic hormone (ADH) with respect to renal salt and water excretion. This was demonstrated by infusing ADH intravenously at rates of 0, 5, and 25, uU/kg/min in three different groups of mongrel dogs which were chemically sympathectomized with guanethidine sulfate. Within each, group infused with constant levels of ADH, NE was infused at increasing rates from 0.05 to 3.2 ug/kg/min during eight consecutive thirty minute periods. Under these conditions NE was diuretic, natriuretic, and increased both osmolar and free water clearance, while ADH had the opposite effects. These effects of NE appear to be the result of decreased permeability of the collecting duct first to solutes and second to water.