[Aqueous dynamics and ciliary epithelium enzyme systems (author's transl)].

Aqueous humour is produced by ultrafiltration (30%) and active ion transport (70%) predominantly achieved by nonpigmented ciliary epithelial cells. They need chemical energy supplied by intracellular metabolisms. Suspensions of isolated ciliary epithelial cells and ciliary cell layers prepared from single rabbit eyes have been assayed for activities of glucose-6-phosphate-dehydrogenase, lactate dehydrogenase, malate dehydrogenase, NAD- and NADP-depending isocitrate dehydrogenase. Levels of enzyme activity were found to be higher in the nonpigmented cell type. Enzyme activity of cell layers exceeded those of isolated cells for technical reasons. By comparing ciliary epithelial enzyme patterns to those of different tissues it may be deduced that ciliary epithelium draws its energy chiefly from pentosephosphate and citric cycle. High levels of lactate dehydrogenase activity suggest special functions of this in enzyme in aqueous formation.