Physiological Mechanisms Regulating Rate of Urinary Flow in Renal Disease. ∗

Abstract

Summary and Conclusions

1. A linear relationship was observed between the urinary osmotic load (mOsm/min.) and the rate of urinary flow (ml/min.) in 7 patients suffering from renal disease. This suggests that osmotic diuresis is the major physiological mechanism regulating the rate of urinary flow in these patients with renal disease. 2. In these patients with renal disease there appears to be a “critical” level of the glomerular filtration I rate, approximately 10 ml/min., at which: a) C_K/C_Cr exceeds 100%; b) V/C_Cr exceeds 15%; c) the antidiuretic response to single intravenous injections of pitressin in physiological dosage (0.57 mU/Kg) is markedly diminished; d) there is an alteration in the relationship between V/C_Cr and the urinary concentrations of sodium, potassium and total solute.