Lithium carbonate increases marrow granulocyte-committed colony-forming units and peripheral blood granulocytes in a canine model.

Psychiatric patients given lithium carbonate (LC) commonly develop granulocytosis of the peripheral blood. This is an important observation with several potential applications in clinical hematology and oncology. In order to study further this phenomenon, we have developed an animal model of LC-induced granulocytosis. Four mongrel dogs weighing 23--28 kg were given commercially available LC in 300 mg capsules by mouth twice daily. Peripheral blood was examined twice weekly and marrow granylocyte-committed colony forming units (CFU-c) were studied weekly. Significant increments of peripheral granulocytes (P = 0.003) and of marrow CFU-c (P =0.001) were noted. An increased number of marrow CFU-c has not been previously reported but is consistent with other knowledge about this phenomenon. We conclude that this convenient animal model may be of value in further studies of LC-induced granulocytosis and its possible applications.