The Tyrosine Hydroxylase antiserum was quality control tested using standard immunohistochemical methods. The antiserum demonstrates strongly positive labeling of rat catecholamine neuron systems using indirect immunofluorescent and biotin/avidin-HRP techniques. Recommended primary dilutions for these methods are provided below. This antibody does not cross react with dihydropterdine reductase, dopamine-B-hydroxylase, phenylethanolamine-N-methyltransferase, phenylalanine hydroxylase or tryptophan hydroxylase using Western blot methods.