Weaning Triggers a Maturation Step of Pancreatic β Cells

Because tissue regeneration deteriorates with age, it is generally assumed that the younger the animal, the better it compensates for tissue damage. We have examined the effect of young age on compensatory proliferation of pancreatic β cells in vivo. Surprisingly, β cells in suckling mice fail to enter the cell division cycle in response to a diabetogenic injury or increased glycolysis. The potential of β cells for compensatory proliferation is acquired following premature weaning to normal chow, but not to a diet mimicking maternal milk. In addition, weaning coincides with enhanced glucose-stimulated oxidative phosphorylation and insulin secretion from islets. Transcriptome analysis reveals that weaning increases the expression of genes involved in replication licensing, suggesting a mechanism for increased responsiveness to the mitogenic activity of high glucose. We propose that weaning triggers a discrete maturation step of β cells, elevating both the mitogenic and secretory response to glucose. [Display omitted] •Compensatory proliferation in pancreatic β cells develops only after weaning•High-fat milk prevents compensatory β cell replication in suckling pups•Glucose-stimulated insulin secretion is improved after weaning Stolovich-Rain et al. show that glucose-stimulated mitochondrial function, insulin secretion, and replication of pancreatic beta cells are facilitated by the process of weaning from high-fat milk to high-carbohydrate chow. Weaning triggers a discrete maturation step of beta cells, elevating the mitogenic and secretory responses to glucose.