Reducing GR numbers (GR^+/null) increases the beta-cell fraction in E18 and adult pancreata. Beta-cell fraction, analysed as the ratio of insulin-positive area to the total tissue area, was increased twofold in GR^+/null E18 fetuses (a) and 1.3-fold in GR^+/null adults (b) compared with that of wild-type age-matched animals. *p<0.05, Mann–Whitney non-parametrical test; n=5 and n=4 (means±SEM) in both groups in E18 fetuses and adult animals, respectively