Enhanced non-electrolyte uptake in vitro by the dog jejunal mucosa in the cholera-toxin-induced secretory phase.

A characteristic secretory response in the dog jejunumis observed following three hours' perfusion with cholera toxin. When this mucosa in the secretory phase is examined in vitro, the steady-state accumulation of phenylalanine and beta-methyl-glucoside is considerably enhanced. Since the initial rates of influx of these substrates are unchanged and the tissue ion contents are the same as normal, it is concluded that the increase in steady-state uptake may be attributed to a change in the rate of efflux of the substrates across the baso-lateral membrane of the cell. This change might be related to the reported collapse of the intercellular channels when the intestine is in a secretory state.