Dopamine-stimulated adenylate cyclase and tyrosine hydroxylase in diabetic rat retina.

The effects of streptozotocin-induced diabetes on the retinal dopaminergic system have been examined in Long-Evans (pigmented) rats. Tyrosine hydroxylase activity was significantly decreased while dopamine-stimulated adenylate cyclase was increased in 2-month-diabetic rats. The observed increase in dopamine-stimulated adenylate cyclase activity in diabetic retinae may be related to neurotransmitter receptor changes because postreceptor activation of adenylate cyclase by guanylyl imidodiphosphate was not altered.