Early disappearance of alpha-transducin in light-induced photoreceptor degeneration in albino rats.

Progressive degeneration of retinal photoreceptor cells occurs in albino rats when exposed to continuous lighting. Three proteins involved in the phototransduction cascade were immunodetected in these cells after various durations of continuous illumination. We found that S-antigen (arrestin) and rhodopsin immunoreactivities persisted for 1-2 months during the degenerative process, whilst immunoreactivity of the alpha subunit of transducin totally disappeared between day 2 and day 4 of continuous light exposure. This suggests that continuous illumination could impair alpha-transducin synthesis, a possible causal factor of photoreceptor damage.