Catecholamine (CA) turnover rates were determined in 6- and 10-week-old turkeys following castration. Dopamine (DA) turnover rates decreased while norepinephrine (NE) and epinephrine (E) turnover rates increased in 10-week-old, but not in 6-week-old, turkeys. The changes in CA turnover rates were accompanied by an enhanced release of LH. Administration of an inhibitor of CA synthesis, α-methyltyrosine (MT), reduced the LH rise that follows castration. The results provide additional evidence for the involvement of catecholaminergic mechanisms in LH release.