Insulin sensitivity and sorbitol production of the normal rabbit corneal epithelium in vitro

Insulin-depleted, normal rabbit corneal epithelium was incubated in vitro in tissue culture medium containing high concentrations of glucose (35 mM). These short-term incubations showed that the epithelium took up glucose equally whether or not insulin had been added to the medium, indicating that corneal epithelium is an insulin-insensitive tissue. Sorbitol accumulation showed that the normal corneal epithelium has a sorbitol pathway which can be activated in the presence of high intracellular glucose. The low level of sorbitol accumulation in these normal epithelia is probably not osmotically significant.