Intrarenal Distribution of Glomerular Filtration in Conscious Rats during Isotonic Saline Infusion

Clausen, G. and I. Tyssebotn. Intrarenal distribution of glomerular filtration in conscious rats during isotonic saline infusion. Acta physiol. scand. 1973. 89. 289–295. Relative individual glomerular filtration rate (gfr) of juxtamedullar (JM) and superficial (S) nephrons was determined in conscious rats by the ¹⁴C ferrocyanide technique. Isotonic saline infused at 250 μd/min × 100 g b.w. for about 60 min reduced fractional Na‐reabsorption by 11 % with no significant change in inulin clearance. The S gfr averaged 90 % of JM gfr both in control and saline loaded animals, but with less scatter in the latter group. Thus the natriuresis produced by acute i.v. isotonic saline loading in conscious rats is not caused by redistribution of filtrate. Extracellular volume expansion Individual nephron filtrate Saline loading Sodium excretion ¹⁴C Sodium ferrocyanide