Efecto del INGAP (Proteína Asociada a la Neogénesis Insular) sobre la secreción de insulina de islotes pancreáticos de ratas adultas y recién nacidas.

BORELLI MI; STOPPIGLIA LF; REZENDE LF; FLORES LE; DEL ZOTTO H; GAGLIARDINO JJ

Rev. Argent. Endocrinol Metab RAEM

Año: 2004 vol. 41 p. 9 - 13

We examined the effects of a pentadecapeptide having the 104–118 aminoacid sequence of islet neogenesis-associated protein (INGAPPP) 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 Ag/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 h-cell size. This first demonstration of the enhancing effect of INGAP-PP on the h-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.