Cyclic GMP metabolic defects in inherited disorders of rd mice and RCS rats.
The inherited diseases of rd mice and RCS rats are compared. The rd disorder is characterized by the failure of rod visual cells to differentiate fully, by the accumulation of cyclic GMP, which results from a reduced level of phosphodiesterase activity, and by the rapid degeneration of visual cells, which is unaffected by light. The RCS rat disorder is characterized by the failure of pigment epithelium cells to phagocytize shed membranes of rod outer segments, which accumulate as debris, by a debris-associated reduction in cyclic GMP content, and by the slow degeneration of visual cells, which is accelerated by light. Both disorders result in blindness and both display abnormalities in cyclic GMP metabolism which occur before visual cells degenerate. Identification of a role for cyclic GMP in visual cell metabolism or function may suggest how either elevated levels of cyclic GMP in rd retinas or reduced levels of cyclic GMP in RCS retinas fit into the pattern of visual cell degeneration.
Lolley
R N
RN
Developmental Neurology Laboratory, V.A. Medical Center, Sepulveda, CA 91343 USA; Department of Anatomy and Jules Stein Eye Institute, University of California, Los Angeles, California 90024 USA.
Farber
D B
DB