The objective of this study is to determine whether abnormal rhythm and amplitude of the oscillation in plasma
motilin concentration are responsible for the abnormal motility observed in patients with diabetic
gastroparesis. We also investigated the effect of
metoclopramide on plasma
motilin concentration and gastrointestinal motility in these patients. In healthy controls, basal plasma
motilin concentration fluctuated in phase with the interdigestive migrating motor complex. All patients with diabetic
gastroparesis did not have
antral phase III activities and had significantly higher basal
motilin concentrations, which maintained a normal oscillatory pattern. Administration of
metoclopramide initiated
antral phase III activities in healthy controls and in patients with diabetic
gastroparesis. These were accompanied by a concurrent rise in plasma
motilin concentration in healthy controls, contrasting with a fall in plasma
motilin concentrations in patients with diabetic
gastroparesis. We conclude that diabetic
gastroparesis is associated with absence of
antral interdigestive migrating motor complex and with elevated plasma
motilin concentration with normal cyclic fluctuations. Our studies also show that
metoclopramide initiates
antral phase III activities in diabetic
gastroparesis independent of plasma
motilin concentration.