Derevianchenko T G, Fedorovich I B, Ostrovskiĭ M A
Tsitologiia. 1985 Oct;27(10):1197-9.
The existence of SH-group concentration axial gradient in frog's retinal rod outer segments has been shown. A diminution of SH-groups in the outer segment apical part points to a damage of the vision pigment during the life span of the rod disks.