LUDWIGS THEORY OF TUBULAR REABSORPTION - ROLE OF PHYSICAL FACTORS IN TUBULAR REABSORPTION

The development of the concept that physical forces in the peritubular surroundings influence absorption across certain epithelial membranes was traced. The question of whether these forces act in a permissive manner by influencing the permeability of the zona occludens (or some other barrier) to various solutes or whether these forces act directly, or both, remains moot. Ludwig''s original vision of the nature of urine formation is apparently, at least partly, applicable to the reabsorption of fluid from the proximal tubule just as it has long been recognized to be valid for the formation of glomerular ultrafiltrate.