Abstract
In an attempt to study the interrelationship between aldosterone, Na balance, prostaglandin (PG) and kallikrein excretion, we investigated the influence of adrenalectomy and aldosterone administration on kallikrein and PG excretion during dietary manipulation of extracellular volume in Sprague-Dawley rats. Adrenalectomy decreased while aldosterone administration increased urinary kallikrein and PG excretion during both low and high Na intake. Aldosterone induced a prompt change in Na/K ratio; however, kallikrein and PG excretion increased gradually during the 7 days of treatment. When the animals were forced into a negative Na balance during the administration of aldosterone by reducing their Na intake, kallikrein and PG excretion still increased but to a lesser extent than on a constant diet. In adrenalectomized rats given only vehicle, shifting the diet to a low Na intake caused a decrease in kallikrein and PG excretion. Corticosterone failed to correct the changes evoked by adrenalectomy, and it did not reproduce the effects of aldosterone. It is concluded that the effect of aldosterone on kallikrein and PG excretion is not mediated by changes in extracellular volume; however, in the absence of aldosterone a change in Na balance itself may influence kallikrein and PG excretion.