Intrarenal Regulating Mechanisms of Renal Function

摘要

In micropuncture experiments in the rat kidney single loops of Henle were perfused in order to measure their reabsorptive characteristics at various perfusion rates. In 56% sodium reabsorption increased in proportion to the increasing perfusion rate and early distal sodium concentration remained constant. In 44% fractional sodium reabsorption decreased with increasing perfusion rate and early distal sodium concentration increased. Micropuncture studies in the rat kidney were performed in order to investigate the intrarenal distribution of single nephron filtrates. Two types of nephrons were defined: (a) superficial nephrons, and (b) juxtamedullary nephrons. In low sodium rats superficial nephron GFR was 23.5 and juxtamedullary GFR 58.2 ml/min x g KW. During high sodium diet superficial GFR increased to 38.1 and juxtamedullary GFR decreased to 16.5 ml/min x g KW. The distributional patterns agree closely with the intrarenal distribution of renin and its dependency on salt intake. A preparative method to purify the renin substrate was developed. This substrate was used in order to measure renin content of single juxtamedullary apparatus. (Author)