Comments in Gastroenterology

LTHOUGH AN EVERTED gut sac can move molecules from mucosal to senosal surfaces, time intact intestine utilizes its circulation as an integral part of the transport process, and blood flow must be considered as a potential rate-limiting step. Time immteraction between the circula-tion and intestinal absorption is a two-way street: absorption influences blood flow and the reverse holds as well. Di-gestion, motility, and intestinal energy consumption also affect blood flow, either by direct local stimulation or through distant release of humoral agents. Time effect of specific nutrients on splanchnic blood flow has been examined. Timere is general agreement that instilla-tion or ingestion of hypertonic glucose solutions into time gut evoked an increase in botim splanchnic and mesentenic blood flows (1-5). The effect of isotonic glucose was variable (2, 3). Pmoteiim immgestion causetl an increase in intestinal blooci flow in humans (6) and in conscious dogs (7). Instillation of gly-cine in the gut loop of an anesthetized dog had time sanme result (2). Mesentenic blood flow was greatly augmented by (iietary fat (8) but mmot by isotonic sa-iimme (2). Ingestion of a mixetl, usual diet in-creased blood flow in time conscious dog (9, 1 1). Once time food was in the gastro-intestinal tract and digestion assumed t