Some biochemical changes in lenses of riboflavin deficient rats.

In order to better understand the role of riboflavin in the lens, we investigated the lenses of rats fed on a riboflavin deficient diet for 7 weeks to determine changes in the inactivation of cortisol, the glucose-6-phosphate dehydrogenase (G-6-PD) activity and the histidine or 5-hydroxytryptophan decarboxylase activity. The cortisol-binding capacity and G-6-PD activity in the lenses of rats fed on a riboflavin deficient diet were found to be decreased as compared with a control. Histidine decarboxylase activity was found twice as high in the riboflavin deficient rats as in the normal lenses however, 5-hydroxytryptophan decarboxylase was somewhat decreased. These findings show that catabolical changes in the metabolism of rat lenses are induced comprehensively by feeding on a riboflavin deficient diet in the same manner as changes are seen in the cataractous lens.