To quantify the role of the kidney in whole body metabolic clearance rate (MRC) from plasma of atrial natriuretic peptide (ANP), synthetic α-human ANP-(1-28) was infused at 200 ng/min to steady-state conditions in chronically instrumented one-kidney conscious dogs. Clearances were measured in dogs with a normally filtering kidney and they were also measured after the glomerular filtration rate (GFR) was reduced to close to zero by acutely inflating a cuff around the renal artery (RAC), which resulted in minimal urine production and renal blood flow reduction to 59% of the testing level. In normal dogs, MCR was 1,090 ± 134 ml/min with renal clearance rate (RCR) contributing only 13.9%. After RAC, MCR fell to 864 ± 151 ml/min, due in part to a fall in RCR (-41.5 ± 12.9 ml/min), but mostly due to a fall in 'rest of the body' (total renal) clearance of ANP. The reduced GFR accounted for virtually all the fall in RCR. Normal plasma ANP half-life was 59.6 ± 7.9 s. In conclusion, MCR of ANP was very high, approaching the cardiac output, suggesting that most of ANP is cleared in one circulation through peripheral tissues. GFR contributed significantly to RCR (~30%) but the contribution of the kidney to whole body MCR was small relative to rest of the body clearance of ANP.
|Journal||American Journal of Physiology|
|Publication status||Published - 1988|