Tyrosine hydroxylase (TH) and dopamine-β-hydroxylase (DBH) activities were measured in various tissues of guinea-pigs 1-21 days after intravenous injection of antiserum against DBH. At 5 days a significant reduction in tissue levels of DBH was observed in all tissues measured although the extent of depletion was variable. TH in the heart and vas deferens showed a parallel reduction to DBH. At 21 days tissue DBH and TH had partially recovered. Plasma DBH was reduced at 21 days whereas adrenal TH was markedly elevated. These findings support the morphological evidence that antibodies against DBH produce a specific degeneration of peripheral noradrenergic nerves.