Dependence on Substrate of the Electrical Potential across the Isolated Gut

Abstract

PUBLISHED reports^1,2 have indicated that fluid and salt transport across the isolated small intestine is very low in the absence of an external supply of substrate. Chemical measurements of net transport have shown that, of the many substrates tested, only glucose is able to support optimal absorption¹. With such measurements, the tissue must be allowed to equilibrate for 20–30 min. before sufficient fluid or salt has been transported to allow accurate chemical measurements. Thus a considerable uncertainty exists as to how rapidly the absorptive process changes when glucose is added to or removed from the bathing media. A clarification of this point would indicate the extent to which utilizable energy is stored in the tissue.