The renal clearance of albumin following intravenous loading of homologous albumin in conscious rats.
Tubular reabsorption of albumin was studied in conscious rats by measuring the renal excretion at various plasma concentrations. The plasma albumin concentration was raised by loading the animals with homologous serum albumin. By using this procedure an average plasma concentration of 54 g/l could be reached, which is about twice the physiological plasma albumin concentration in untreated rats. Throughout the experiments the glomerular filtration rate was determined by the total plasma slope clearance of 51Cr-EDTA. Following the albumin load, the 51Cr-EDTA clearance remained at 54.8 +/- 12.2 ml/min/m2 body surface. By correlating renal albumin excretion and plasma albumin concentration, the sieving coefficient of albumin, phi, of 2.35 x 10(-4), the renal albumin threshold of 38 +/- 5 g/l, and the maximal tubular transport rate of albumin of 9.6 +/- 2.6 micrograms/min/g kidney weight could be calculated (mean +/- SD). There were some variations among the animals, resulting in a fairly large standard deviation. However, these values are in agreement with recent micropuncture data.
D000818:Animals; D003243:Consciousness; D004056:Differential Threshold; D005260:Female; D005919:Glomerular Filtration Rate; D007275:Injections, Intravenous; D007668:Kidney / Q000378:metabolism*; D007684:Kidney Tubules / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D012709:Serum Albumin / Q000008:administration & dosage / Q000378:metabolism*
D012709:Serum Albumin