Influence of glucose, fructose and aldose reductase inhibition on retinal sorbitol metabolism.

The sorbitol shunt has been studied in bovine retinal tissue at incubation times from 1 to 24 h. It was shown that an elevated glucose concentration (22 mM) of the medium was accompanied by a slight increase in sorbitol content already after 3 h. At longer incubation times, but lower glucose concentration (11.1 mM) there was a similar increase. Addition of an aldose reductase (AR) inhibitor prevented the sorbitol increase. Addition of fructose to the medium significantly increased the sorbitol accumulation above the effect seen with glucose alone and this effect was not influenced by the AR inhibitor. Thus the sorbitol concentration in the retina may be increased after a short incubation time and further enhanced by the presence of fructose.