[In vitro incubation of lenses. Model for testing substrate utilization of substances of the energy metabolism, demonstrated with bencyclane-hydrogen-fumarate (author's transl)].

When bovine lens homogenate was treated with bencyclane-hydrogen-fumarate, the carbohydrate metabolism was activated. This may chiefly be due to the fumarate part of the substance. A 24 H In vitro incubation of whole bovine lenses in TC-199 with and without bencyclane-hydrogen-fumarate did not show the above effect. On the model of former investigations by J.E. Harris et al. we modified the test procedure by selecting the medium and the time of incubation so that the endogenous carbohydrates of the lens were consumed, thus creating new metabolic balances. This metabolic condition allows investigations intended to activate metabolic processes and to restore the steady state of metabolic parameters. We investigated the effect of bencyclane-hydrogen-fumarate using the same method and found that given certain conditions the lens recovers when incubated for 2 h in TC-199 (containing 1 g glucose/1) with addition of a 10(-4) M solution of bencyclane-hydrogen-fumarate. The ATP-content of these lenses in particular gives proof of this result. As already observed in former investigations on homogenates, this effect is probably due to metabolization of the fumarate part of the bencyclane-hydrogen-fumarate by the citric acid cycle. The method used explains the differences observed when using lens homogenates or whole lenses under the same experimental conditions.