Genetically modified rice seeds accumulating GLP‐1 analogue stimulate insulin secretion from a mouse pancreatic beta‐cell line

Abstract
Glucagon‐like peptide‐1 (7‐36) amide (GLP‐1) is the most potent physiological insulinotropic hormone in humans. We produced large amounts of a GLP‐1 analogue, [Ser8, Gln26, Asp34]‐GLP‐1, which is resistant to trypsin‐digestion, as part of a chimeric rice seed storage protein, a 26 kDa globulin, in genetically modified rice seeds. Junction sites between GLP‐1 analogue and globulin were replaced by tryptic cleavage sites. The highest level of GLP‐1 analogue accumulation was ≈20–50 μg per seed. We found that GLP‐1 analogue derived from trypsin‐digested genetically modified rice seeds stimulated insulin secretion from a mouse pancreatic beta‐cell line, MIN6.