Functional characterization of estrogen and glucocorticoid responsive elements in the rat oxytocin gene.
Expression of the gene encoding the oxytocin precursor occurs in the hypothalamus and, to a lesser extent, in a number of peripheral organs, the tissue-specific regulatory mechanisms of which are largely unknown. By DNA sequence analysis several elements upstream of the transcriptional start point of the rat oxytocin gene were identified matching the consensus sequence of enhancers inducible by estrogen or glucocorticoids, respectively. Their general transactivating capacities were investigated using heterologous gene constructs and revealed that the rat oxytocin gene harbours two functional estrogen responsive elements near the transcription initiation site, one of which is conserved in the respective human gene. In addition, one enhancer conferring glucocorticoid responsiveness to a reporter gene is located at nucleotide residues -2449 to -2464. These data might indicate a steroid hormone-mediated influence on oxytocin gene expression in the central nervous system and/or the periphery.