WATER FLOW THROUGH FROG GASTRIC MUCOSA

Abstract

Experiments were performed on water transport across the isolated gastric mucosa of the frog. (1) The unidirectional diffusion flow using tritiated water as a tracer was 180 [mu]l/cm2 hour. (2) An osmotic net flow of 15 [mu]l/cm2/hour, comparable in volume with that spontaneously secreted, was produced by doubling the normal osmolarity on the secretory side of the mucosa. Net flow measurements were made using a volume chamber accurate to [plus or minus] 2 [mu]l. Measurements of the restriction offered by the membrane to diffusion of various sized molecules and ions indicate 93% of the pore area was contributed by pores of 2.5 A radius and 7% by pores of 60 A radius.