In the PR rat, prevention of later diabetes following neonatal exendin-4 treatment reflects reversal of epigenetic changes induced by PR in the Pdx-1 promoter by late gestation, that normally worsen with age and lead to decreased Pdx-1 expression, loss of β-cell function and subsequent loss of β-cell mass postnatally [15], [16], [19]. Here, PDX1 is linked to diabetes mellitus.