Figure 3.
Inhibition of Isomerase activity in chicken RPE homogenate by NEM, 2,2′-bipyridine, and progesterone. Isomerase assays were performed on chicken RPE homogenates in the presence or absence of indicated inhibitors. The effect of treatment was determined by measuring the change in 11-cis retinol synthesized from treated RPE homogenate.from 11-cis retinol synthesized in control experiments. (A) Effect of NEM on RPE homogenate from control was -0.034 ± 0.004 nmol/mg. 2,2′-Bipyridine also provided an inhibitory effect on 11-cis retinol synthesis in RPE homogenate (-0.039 ± 0.003 nmol/mg). Progesterone had no significant effect on RPE retinoid isomerase activity (0.004 ± 0.013 nmol/mg). (B-D) Representative HPLC chromatograms of retinoid extracts from control and treated (NEM, 2,2′-Bipyridine, and progesterone from left to right) RPE homogenates. Insets show absorbance spectrum of HPLC peak indicated by arrow (11-cis retinol). (n = 3)