Summary: Data from studies indicate that blood glucose levels may be influenced by stimulation of central Dl and D2 dopamine receptors. This is modulated by central dopamine receptor status. We studied apomorphine-induced increase in blood glucose levels in Parkinson's disease compared with those in Parkinsonian syndromes unresponsive to dopaminergic drugs. Results indicate that apomorphine-induced blood glucose level increases are significant only in Parkinson's disease. As in the animal, this could possibly be explained by central dopamine receptor status.