Integration of renal and ureteral function by intraluminal pressure.

Abstract

URINE FORMATION, composition, and transport are profoundly influenced by pressures and other hydraulic factors. Our purpose is to show how intraluminal pressures, from glomerulus to ureter, can alter homeostasis and how pressure increases can cause the mammalian kidney to lose its inherent gradients. In the glomerulus of the dog and rat, capillary filtration pressure has been deduced to be 80 to 100 cm of water, which is one-half to two-thirds systolic blood pressure.1,2The familiar Starling principle summarizes the relationships of hydrostatic and oncotic pressures; the ultimate energy is derived from the force of cardiac contraction.3 In the tubule of the proximal convolution, micropuncture studies have shown the pressure to be 14 cm of water. In the distal convolution the level is 10 cm of water, rising to 20 cm of water with diuresis, and still higher with partial obstruction.4The renal pelvis in the dog