Maternal Exposure to Bisphenol-A During Pregnancy Increases Pancreatic β-Cell Growth During Early Life in Male Mice Offspring

Alterations during development of metabolic key organs such as the endocrine pancreas affect the phenotype later in life. There is evidence that in utero or perinatal exposure to bisphenol-A (BPA) leads to impaired glucose metabolism during adulthood. However, how BPA exposure during pregnancy affects pancreatic beta-cell growth and function in offspring during early life has not been explored. We exposed pregnant mice to either vehicle (control) or BPA (10 and 100 mu g/kg.d, BPA10 and BPA100) and examined offspring on postnatal days (P) P0, P21, P30, and P120. BPA10 and BPA100 mice presented lower birth weight than control and subsequently gained weight until day 30. At that age, concentration of plasma insulin, C-peptide, and leptin were increased in BPA-exposed animals in the nonfasting state. Insulin secretion and content were diminished in BPA10 and maintained in BPA100 compared with control. A global gene expression analysis indicated that genes related with cell division were increased in islets from BPA-treated animals. This was associated with an increase in pancreatic beta-cell mass at P0, P21, and P30 together with increased beta-cell proliferation and decreased apoptosis. On the contrary, at P120, BPA-treated animals presented either equal or decreased beta-cell mass compared with control and altered fasting glucose levels. These data suggest that in utero exposure to environmentally relevant doses of BPA alters the expression of genes involved in beta-cell growth regulation, incrementing beta-cell mass/area, and beta-cell proliferation during early life. An excess of insulin signaling during early life may contribute to impaired glucose tolerance during adulthood.