Since glucagon-like peptide-1 (GLP-1) is the most potent insulinotropic hormone
known and has been shown to stimulate insulin secretion strongly in patients with
type II diabetes, this invention uses GLP-1 or its biologically active analogues
in -cell stimulatory tests in order to test -cell function in a simple
way. The test provides information about insulin secretory capacity, is easy and
reproducible and has insignificant side effects.