Quantitative assessment of CYP11B1 and CYP11B2 expression in aldosterone-producing adenomas

Background: The presence and pathophysiological role of CYP11B1 (11β-hydroxylase) gene in the zona glomerulosa of human adrenal cortex is still controversial. Methods: In order to specifically quantify CYP11B1, CYP11B2 (aldosterone synthase) and CYP17(17α-hydroxylase) mRNA levels, we developed a real-time RT-PCR assay and examined the expression in a series of adrenal tissues, including six normal adrenals from patients adrenalectomized for renal cancer and twelve aldosterone-producing adenomas (APA) from patients with primary aldosteronism. Results: CYP11B1 mRNA levels were clearly detected in normal adrenals, which comprised both zona glomerulosa and fasciculata/reticularis cells, but were also measured at a lower range (P < 0.05) in APA. The levels of CYP11B2 mRNA were lower (P < 0.005) in normal adrenals than in APA. CYP17 mRNAlevels were similar in normal adrenals and in APA. In patients with APA, CYP11B2 and CYP11B1 mRNA levels were not correlated either with basal aldosterone or...