DIBUTYRYL CYCLIC ADENOSINE-MONOPHOSPHATE STIMULATES THE SODIUM-PUMP IN RABBIT RENAL CORTICAL TUBULES

The elevation in oxygen consumption (QO(2)) observed following additio n of the sodium ionophore nystatin in suspensions of rabbit renal prox imal tubules was significantly increased by 1 mM dibutyryl cyclic aden osine monophosphate (db-cAMP). The QO(2) after subsequent addition of strophanthidin to block the sodium pump was unnaffected by db-cAMP. Ho wever, 10 mu M forskolin in the presence of 100 mu M IBMX had no signi ficant effect on the QO(2) observed following addition of either nysta tin or strophanthidin. Nevertheless, we can conclude that db-cAMP does stimulate the sodium pump activity independently of sodium transport mechanisms in the rabbit renal proximal tubule.