Regulation of aromatase cytochrome P-450 (estrogen synthetase) transcripts in the quail brain by testosterone.
Harada N., Yamada K., Foidart A., Balthazart J.
The aromatase cytochrome P-450 (P-450AROM) cDNA, which was identified by homologies in the DNA and in the deduced amino acid sequences with human P-450AROM cDNA, was isolated from a brain cDNA library of Japanese quail, demonstrating the presence of RNA transcripts of P-450AROM in the quail brain. To determine trace amounts of P-450AROM mRNA in the brain and to examine the effects of testosterone on its expression, a quantitative PCR method of RNA transcripts was developed. Brain total RNA was subjected to reverse transcription reaction and then quantitated by PCR from cDNA with a fluorescent dye-labeled primer. The quantity of P-450AROM mRNA was calculated by using an internal standard of modified P-450AROM (m-P-450AROM) RNA. The brain P-450AROM was primarily transcribed in the hypothalamus area (1.15 +/-0.14 amol/micrograms of RNA) and traces of transcripts only were detected in the cerebellum (0.038 +/-0.005 amol/micrograms of RNA). The P-450AROM mRNA in the hypothalamus of castrated quail was low (0.270 +/-0.078 amol/micrograms of RNA) and increased 4-to 5-fold following treatment with testosterone. These results demonstrate, for the first time, that the increase in P-450AROM activity that is observed in the brain following treatment with testosterone results from a pretranslational regulation of the P-450AROM by androgens.
Brain Res. Mol. Brain Res. 15:19-26(1992) [ PubMed | SRS | CiteXplore ]
