Lithium in diabetes mellitus: a paradoxical response.

An unusual hyperglycemic effect of lithium was observed in a patient suffering from diabetes mellitus and mania. In the presence of constant insulin dosage, high serum lithium levels were correlated with high fasting bloos sugar, while lowering of the lithium level led to a lowering the fasting blood sugar. These observations are discussed in terms of the effects of lithium on glucose metabolism and with particular emphasis on the ability of lithium to increase the release of glucagon.