The neuropeptide APGWamide induces imposex in the mud snail, Ilyanassa obsoleta

We investigated whether neuropeptides which control sexual differentiation in mollusks can induce imposex—a condition where female snails grow male accessory sex organs after exposure to tributyltin (TBT). Mud snails, Ilyanassa obsoleta, were dosed with one of four neuropeptides: APGWamide, conopressin, LSSFVRIamide, or FMRFamide for seven or fourteen days. TBT and testosterone (T) were used as positive controls and induced imposex as expected. APGWamide significantly induced imposex, with a threshold dose near 10 − 16 moles. The other neuropeptides had no effect on imposex induction. We propose that TBT could act as a neurotoxin to induce imposex via abnormal release of APGWamide.