Effect of neonatal corticoid treatment on tryptophan and serotonin metabolism.

Glucocorticoid administration to newborn rats leads to the premature induction of hepatic tryptophan oxygenase. This is accompanied by a retardation of the developmental increase in brain serotinin both in regions of serotoninergic cell bodies and in terminal projection areas. The magnitude of the fall in serotonin is relatively small. This appears due, at early ages to the concomitant induction of brain tryptophan hydroxylase and at late periods to retarded development of the blood brain barrier against tryptophan.