Postprandial changes of renal blood flow. Studies on conscious dogs on a high and low sodium intake.

Postprandial renal blood flow was studied in 14 conscious dogs on a chronic high and low sodium intake on 72 days after implantation of an electromagnetic flow transducer around the left renal artery. Fasting renal blood flow was 11.7 plus or minus 3.2 ml/min with kg on high socium intake (43 days) and 11.5 plus or minus 3.3 ml/min with kg on low sodium intake (29 days). During ingestion no change of renal blood flow occurred; mean arterial pressure rose transiently. During digestion renal blood flow increased always and was, like the fasting renal blood flow of dogs on a high sodium intake was 41 plus or minus 23%, and of dogs on a low sodium intake 35 plus or minus 15% referring to fasting controls; peak increase mostly occurred between 60 and90 min postprandially and was due to a decrease of renal vascular resistance. Renal blood flow also increased after augmentation of intravascular volume by an intravenous infusion; volume receptors may be involved.