Uptake of Tritiated Retinaldehyde by the Visual Pigment of Dark-adapted Rats

Abstract

RHODOPSIN bleaches in the light to opsin and free retinaldehyde. In the retina of the living albino rat, this retinaldehyde is reduced to retinol, which then flows into the pigment epithelium¹. The process reverses during dark-adaptation, and continues until the visual pigment has regenerated. Because rhodopsin is stable at physiological pH and temperature, it seems unlikely that continued turnover would occur in animals kept in total darkness. Our experiments demonstrate, however, that this process takes place to a marked degree. We recently gave a brief account of our findings².