Lithium accumulation in some endocrine tissues.

Lithium levels were measured in several tissues of rats after oral lithium administration for various periods of time. The lithium levels in the brain approached those of the serum while there was a marked accumulation of lithium in the pituitary and thyroid glands. When lithium was stopped there was no noticeable lag in clearance for any of the tissues examined, with the pituitary maintaining a significant elevation of lithium over the serum levels. Animals receiving lithium had higher levels of adrenal corticosterone under quiescent conditions and higher levels of plasma corticosterone thirty minutes after a brief electric footshock.