Chromophores in the extraretinal photoreceptor (pineal organ) of teleosts.

We have demonstrated, using a highly sensitive high performance liquid chromatography technique, that the pineal organ (epiphysis cerebri) of the rainbow trout contains both 11-cis-retinal and 11-cis-3-dehydroretinal. These compounds were assumed to be the chromophores of pineal photopigments, because they were isomerized to all-trans forms by light-adaptation. The quantity of chromophores in the dark-adapted pineal organ was extremely low (9.2-29.1 pmol/pineal), corresponding to approximately 1/300-1/1000 of that of the retina.