Lithium chloride as an enhancing agent for metaphase preparations from rodent lymphocytes

Circulating lymphocytes of many mammals, especially rodents, have proven refractory to PHA stimulation of mitotic activity. Addition of small amounts of lithium chloride to the culture medium removes the refractoriness and increases the yield of metaphase cells 7 fold. This simple procedure makes possible the routine use of circulating lymphocytes in rodent karyology.