Detection and Regulation of the Tyrosine Hydroxylase mRNA Levels in Rat Adrenal Medulla and Brain Tissues

The catecholamines are an important class of neurotransmitters present both in the central and peripheral nervous systems. They constitute a useful model for the analysis of the mechanisms involved in the regulation of gene expression during development. Tyrosine hydroxylase (tyrosine 3-monooxygenase; l-tyrosine, tetrahydropterine:oxygen oxidoreductase [3-hydroxylating], [EC 1.14.16.2]), the rate-limiting enzyme in the synthesis of catecholamine, has been intensively investigated because of its key role in the physiology of adrenergic neurons. The regulation of its expression has been shown to be influenced by transsynaptic humoral orthograde and retrograde processes during development (Edgar and Thoenen 1978; Black and Patterson 1980; Le Douarin 1980).