Figure 1.

Under hyperglycaemic conditions glucose enters vascular and retinal cells via the GLUT 1 transporter and is metabolised by glycolysis. Accumulation of an intermediate in glycolysis, glyceraldehyde-3-phosphate (G-3-P), leads to de novo synthesis of DAG, which in turn activates one or more PKC isozymes, especially but not exclusively PKC-β. PKC mediated phosphorylation of transcription factors, cytoskeletal proteins, enzymes and transporters in turn affects many of the pathophysiological features of diabetic retinopathy.