Islet Neogenesis-Associated Protein (INGAP)-Positive Cell Mass, B-Cell Mass and Insulin Secretion: Their Relationship During the Fetal and Neonatal Periods

MADRID V; BORELLI MI; MAIZTEGUI B; FLORES L; GAGLIARDINO JJ; DEL ZOTTO H

PANCREAS.

LIPPINCOTT WILLIAMS & WILKINS

Lugar: Philadelphia; Año: 2012

0885-3177

Objective: To study the chronological appearance of pancreatic Islet Neogenesis-Associated Protein (INGAP)-positive cells and its correlation with the increase in B-cellmass and function in fetal and neonatal rats.Methods: Normal Wistar rat embryos (E) at gestational days 15, 17 and 19 (E15, E17,E19) and 7-day-old postnatal rats (P7) were sacrificed to determine body and pancreasweight, blood glucose, glucose and arginine-induced insulin secretion in vitro, realtimePCR of Pdx1 and Ngn3, and quantitative immunomorphometric analysis of B-cellreplication and apoptosis rate, cytokeratin and INGAP cell mass, and Pdx-1- and Ngn-3-positive cells.Results: Body and pancreas weight increased with age (P7>E19>E17>E15; P < 0.05).Neonates had higher blood glucose concentrations than embryos (P < 0.05). Werecorded a simultaneous and significant age-dependent trend of increase in thenumber of B- and Pdx-1-positive cells, B- and cytokeratin-positive cell mass and B-cellcapacity to release insulin in response to glucose and arginine, and decreased B-cellapoptotic rate. These changes closely paralleled the increase in INGAP-positive-cellmass.Conclusions: These findings suggest that INGAP exerts a positive modulatory effectupon B-cell mass and its secretory function in fetal and neonatal rats, thus becoming anew component in the multifactorial regulation of such processes.