Evaluation of β-cell mass and function in the Göttingen minipig

Increased knowledge about β-cell mass and function is important for our understanding of the pathophysiology of type 2 diabetes (T2DM). The relationship between the two is difficult to study in humans, whereas animal models allow studies of consequences of, for example, reduction of β-cell mass and induction of obesity and procurement of the pancreas for histological examination. An overview of results obtained in the Gottingen minipigin relation to β-cell function, and mass is provided here. Effects of a primary reduction of β-cell mass have indicated that not all of the defects of pulsatile insulinsecretion in human T2DM can be explained by reduced β-cell mass. Furthermore, induction of obesity has shown deterioration of β-cell function and morphological changes in the pancreas. As in humans, obesity leads to an increased β-cell volume in the minipig, and based on the increased number of islets, neogenesisof islets is an important factor in expansion of β-cell mass in this species. Measurement of β-cell function as an estimate of β-cell mass is, at present, the only method possible in humans, and this approach has been validated using lean and obese minipigs with a range of β-cell mass. The effects on β-cell function and mass of obesity of longer duration and/or more pronounced hyperglycaemia remains to be determined, but the models developed so far represent a valuable tool for such investigations.