Besides stimulation of the postprandial insulin secretion, GLP1 may induce beta cell hypertrophy or an increase in the number of beta cells by inhibiting apoptosis and increasing replication. Nesidioblastosis (beta cell hypertrophy, islet hyperplasia and increased beta cell mass) is associated with HH after RYGB in some cases, however, nesidioblastosis was not found in these patients and an overexpression of GLP1-receptors in individual islets was not found.