Regulation of glucose metabolism was evaluated by oral glucose tolerance test (OGTT) in patients with familial amyloidotic polyneuropathy (FAP). Upon oral administration of a loading dose of glucose, plasma levels of glucose, insulin and glucagon changed abnormally in all FAP patients tested. Although plasma levels of glucose and insulin in the fasted patients were within normal ranges, 33% of FAP patients showed hypoglycemia after transient hyperinsulinemia during the examination. Furthermore, another three patients showed transient hypoglycemia during their daily life. Thus, perturbed glucose metabolism should be taken into account for treating patients with FAP. The salivary glands as well as the lacrimal glands showed transient hypersecretion after chewing a gum. Histochemical analysis at autopsy revealed significant amyloid deposition in the stroma, nerves and vessels of the pancreas, but not in Langerhans islets. Similar appearance was recognized in the salivary glands. These results suggest that denervation supersensitivity might occur not only in the exocrine glands but also in the endocrine gland.