INGAP-related pentadecapeptide: its modulatory effect upon insulin secretion
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Updated: Aug 16, 2026

Homogeneous Time-resolved Förster Resonance Energy Transfer-based Assay for Detection of Insulin Secretion
Published on: May 10, 2018
María I Borelli1, Luiz F Stoppiglia, Luiz F Rezende
1CENEXA-Center of Experimental and Applied Endocrinology (UNLP-CONICET, PAHO/WHO Collaborating Center), National University of La Plata School of Medicine, La Plata, Argentina.
Abstract:
We examined the effects of a pentadecapeptide having the 104-118 aminoacid sequence of islet neogenesis-associated protein (INGAP-PP) on insulin secretion, and the morphological characteristics of adult and neonatal pancreatic rat islets cultured in RPMI and 10 mM glucose for 4 days, with or without different INGAP-PP concentrations (0.1-100 mug/ml). A scrambled 15 aminoacid peptide was used as control for the specificity of INGAP-PP effect. Cultured neonatal and adult islets released insulin in response to glucose (2.8-16.7 mM) in a dose-dependent manner, and to leucine and arginine (10 mM). In all cases, the response was greater in adult islets. INGAP-PP added to the culture medium significantly enhanced glucose- and aminoacid-induced insulin release in both adult and newborn rats; however, no changes were observed with the scrambled peptide. Similar results were obtained incubating freshly isolated adult rat islets with INGAP-PP. Whereas INGAP-PP did not induce significant changes in islet survival rate or proportion/number of islet cells, it increased significantly beta-cell size. This first demonstration of the enhancing effect of INGAP-PP on the beta-cell secretory response of adult and newborn islets opens a new avenue to study its production mechanism and potential use to increase the secretory capacity of endogenous islets in intact animals or of islets preserved for future transplants.
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