Anatomic distribution and regulation of aromatase gene expression in the rat brain

Charles E. Roselli, Salah E. Abdelgadir, Oline K. Rønnekleiv, Scott A. Klosterman

Research output: Contribution to journalArticlepeer-review

87 Scopus citations

Abstract

Recent evidence suggests that two cytochrome P450 aromatase (P450(arom)) mRNA transcripts are present in the rat brain. One of these contains the entire 5'-coding sequence and correlates with the presence of functional enzyme. We designed a new 255-base pair P450(arom) probe (AROM255) that recognizes only this full-length P450(arom) mRNA. Ribonuclease protection assays verified that the cRNA probe synthesized from this construct recognized a single RNA species in brain tissues that express aromatase activity, but not in the cingulate cortex, an area previously shown to contain only the alternate transcript. Moreover, the P450(arom) mRNA content of the preoptic area was significantly lower in castrates than in intact males or testosterone (T)-treated castrates. We employed 33P-labeled cRNA probes to examine the distribution of P450(arom) mRNA by in situ hybridization. High levels of mRNA were detected in the medial preoptic nucleus (MPN), bed nucleus of the stria terminalis (BnST), and medial amygdala (MA). Lower levels were found in the ventromedial hypothalamic nucleus and cortical amygdala. The magnitude of the hybridization signal in the BnST and MPN was greater in males than in females. Treatment with T propionate significantly increased hybridization signal in BnST, MPN, and MA. These results confirm the anatomic distribution of P450(arom) mRNA within hypothalamic and limbic nuclei of the adult male rat and demonstrate that steady state concentrations are regionally regulated by T. Moreover, they demonstrate the necessity of using a molecular probe that can distinguish between P450(arom) variants in the brain.

Original languageEnglish (US)
Pages (from-to)79-87
Number of pages9
JournalBiology of reproduction
Volume58
Issue number1
DOIs
StatePublished - Jan 1998

ASJC Scopus subject areas

  • Reproductive Medicine
  • Cell Biology

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