1. The α-aminoisobutyric acid flux from lumen to blood of the isolated Cecropia midgut is around 17 µmole/h, while the amino acid flux in the opposite direction is on average 0.3 µmole/h.
2. The amino acid uptake is inhibited by lack of oxygen. It is suggested that the amino acid transport from lumen to blood is an active process.
3. The amino acid uptake is inhibited by short-circuiting the midgut potential, indicating that there is no direct correlation between the active transport of potassium and the uptake of the amino acid by the midgut.