EXPRESSION THE PUTATIVE TRANSCRIPTION FACTOR NOR-1 IN THE NERVOUS, THE ENDOCRINE AND THE IMMUNE-SYSTEMS AND DEVELOPING BRAIN OF THE RAT

NOR-1 is a novel member of the NGFI-B/RNR-1 subfamily within the nucle ar receptor superfamily, and has been implicated in signal transductio n mediated by various second messengers. To investigate the physiologi cal role of NOR-1, we examined its gene expression in various adult ra t tissues and developing rat brain by the quantitative reverse transcr iption-polymerase chain reaction using in vitro synthesized RNA as an internal standard. The NOR-1 gene was expressed in all tissues examine d, but predominantly in the cerebral cortex and pituitary glands. Thym us, adrenal glands, spleen, epididymis, submandibular glands and defer ent ducts showed moderate expression. In the brain, NOR-1 gene express ion was developmentally regulated, with the peak levels on gestational day 18. These findings suggest a ubiquitous role of NOR-1 in signal t ransduction in diverse tissues. These findings also suggest that the n ervous, endocrine and immune systems may be highly exposed to NOR-1-in ducing stimuli under normal conditions in adult rats. Developing rat b rain cells may most frequently receive the relevant signal on day 18 o f gestation.