The figure shows lanes from immunoblots probed with antibodies against the various prolyl hydroxylases. Abbreviations: Prolyl hydroxylase (P4Hα1), PHD prolyl hydroxylase 1 (PH 1), PHD prolyl hydroxylase 2 (PH 2), PHD prolyl hydroxylase 3 (PH 3), PHD prolyl hydroxylase 4 (PH 4). The known sizes of the various hydroxylases are shown at the bottom of the figure. To show the absence or a low level of a hydroxylase, 500 islets instead of 50 islets were used.