Potassium exchange between bathing solution and midgut of Hyalophora cecropia and time delay for potassium flux through the midgut.

Exchange between potassium of the isolated midgut of the American silkworm Hyalophora cecropia and the bathing solutions has been determined by different authors, but with contradictory results. Therefore the experiments were repeated with another technique and the exchange determined for varying time intervals. It was found that the exchange was fast-half of the midgut K was exchanged in 2-3 minutes, which confirms the earlier findings by Harvey & Zerahn (1969).