1938-2014 Melis Karaca islets In vivo functional heterogeneity among β-cells Landes Bioscience 2010-03-01 124 - 126 Islets 2-2 Landes Bioscience The concept of functional heterogeneity among β-cells proposes that each cell differs in its sensitivity to glucose and is recruited in a glucose-dependent manner into both biosynthetic and secretory active states in order to adapt insulin secretion to the metabolic environment. Therefore, characterization of β-cell populations with different metabolic sensitivities would lead to the development of new therapeutic strategies. Based on heterogeneous surface PSA-NCAM expression on β-cells, we have recently characterized two groups of cells, namely β^high and β^low-cells, in rat. Differences in insulin secretory capacity and in gene expression profiles suggest that βlow-cells are immature and/or non-functional cells in contrast to highly glucose responsive fully functional β^high-cells. Moreover, the relative distribution of β^high and β^low-cells correlated with physiological and pathological states regarding the functional β-cell mass. Here we summarize our main results on β^high and β^low-cell populations and discuss some of the open remaining questions. http://dx.doi.org/10.4161/isl.2.2.10945 http://www.landesbioscience.com/journals/islets/article/10945/ article Article Addendum