title: Mechanism of decrease in plasma renin activity during volume expansion.
abstract: The importance of filtered load of sodium and extracellular volume expansion (ECVE( per se on plasma renin activity (PRA) was studied in two groups of hydropenic dogs. Group I protocol consisted of bilateral ureteral obstruction (UO) followed by isotonic ECVE and finally UO release. During UO, PRA rose significantly above control (15.4 leads to 41.7 ng/ml per h). Superimposition of ECVE did not significantly alter PRA, but UO release returned PRA toward control (24.8 ng/ml per h). Fractional sodium excretion (FE(Na)) after UO release was higher than control (0.6 leads to 12.6%). In group II, ECVE preceded UO and caused a fall in PRA below control (16.8 leads to 4.8 ng/ml per h). FE(Na) was significantly increased over control (0.3 leads to 14.7%). Superimposition of UO reversed the fall in PRA to a value not significantly different from control. On release of UO PRA fell, but not significantly, whereas FE(Na) fell to 12.6%, a value not different from that during ECVE alone. The results indicate that filtration is required for ECVE to elicit a fall in PRA, under the present experimental condition.
mesh_terms: D000818:Animals; D001794:Blood Pressure; D001798:Blood Proteins; D004285:Dogs; D005919:Glomerular Filtration Rate; D007684:Kidney Tubules / Q000502:physiology*; D008297:Male; D009318:Natriuresis; D009994:Osmolar Concentration; D011188:Potassium / Q000097:blood; D012083:Renin / Q000097:blood*; D011984:Sensory Receptor Cells / Q000502:physiology*; D012964:Sodium / Q000097:blood; D012965:Sodium Chloride / Q000494:pharmacology; D014517:Ureteral Obstruction; D014556:Urine
chemical_list: D001798:Blood Proteins; D012965:Sodium Chloride; D012964:Sodium; D012083:Renin; D011188:Potassium