Effect of DDAVP on plasma renin activity in man.

We have investigated in eight healthy persons the effect of a single intranasal dose of 40 microgram DDAVP on plasma renin activity (PRA) in the upright posture. During normal sodium intake there were no differences in the PRA values between the time-control and DDAVP studies. However, during sodium restriction in four subjects with higher initial PRA, DDAVP induced a 40% decrease, lasting no longer than 45 minutes. There was no change in PRA after DDAVP in the other four subjects with much lower initial levels. Although no major or consistent suppressive influence could be demonstrated in the present study, in certain persons with highly stimulated initial PRA levels a transitory slight depression may be expected after a pharmacological dose of DDAVP.