Regional sensitivity to hypoglycemia within the rabbit lens epithelium

Paired rabbit lenses were kept in organ culture; one of the lenses was subjected to hypoglycemia, and the other served as control. The lens changes were followed and examined by photomacrography, light microscopy of the intact lens, and light and electron microscopy at different time intervals. The possibility of reversing the morphological changes was evaluated at different times by replacing the hypoglycemic medium with a normal glycemic one. The central zone of the lens epithelium was affected first through the formation of large extracellular vacuoles. These changes were reversible. Subsequently, the central lens epithelial cells showed severe swelling and breakdown of the lens membranes. These changes were not reversible. With time the epithelial changes spread from the central zone towards the equator. Lens fiber swelling followed the severe epithelial damage. These findings show that there is a regional sensitivity to hypoglycemia within the lens epithelium. The results are discussed in relation to hexokinase activity.