Retinal enzyme activities under hypoxic conditions prior to neovascularization.

In an effort to demonstrate biochemical changes occuring in malperfused retinas, oxygen-induced retrolental fibroplasia was produced in kittens. Immediately before the onset of vasoproliferations, that is in the stage of maximal hypoxia, the activities of lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G-6-PDH), malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICDH) were determined. The activity of MDH was found to be significantly decreased, whereas the activities of the other enzymes showed no major changes.