The physiological mechanisms underlying pancreatic beta-cell mass homeostasis are complex and not fully resolved. Here we examined the factors contributing to the increased beta-cell mass (BCM) following a mild glucose infusion (GI) whereby normoglycemia was maintained through 96 h. We used morphometric and immunochemical methods to investigate enhanced beta-cell growth and survival in Sprague-Dawley rats. By 48 h, BCM was elevated >2.5-fold over saline-infused controls and increased modestly thereafter. Unexpectedly, increases in beta-cell proliferation were not observed at any time-point through 4 days. Instead, enhanced numbers of insulin⁺ cell clusters and small islets (400-12,000 µm²; ~ 23 to 124 µm diameter), mostly scattered among the acini, were observed in the GI rats by 48 h despite no differences in the numbers of medium to large islets. We have previously shown that increased beta-cell growth in rodent models of insulin resistance and pancreatic regeneration involve increased activated Akt/PKB, a key beta-cell signaling intermediate, in both islets and endocrine cell clusters. GI in normal rats also leads to increased Akt activation in islet beta-cells, as well as in insulin⁺ and insulin^- cells in the common duct epithelium and endocrine clusters. This correlated with strong Pdx1 expression in these same cells. These results suggest that mechanisms other than proliferation underlie the rapid beta-cell growth response following a mild glucose infusion in the normal rat and involve Akt-regulated enhanced beta-cell survival potential and neogenesis from epithelial precursors.