Abstract:

Objective   To determine whether steroidogenic enzyme expression is associated with the steroid secretory pattern of subclinical Cushing’s syndrome (SCS) by investigating the expression of CYP17 and CYP11B1 in SCS adenomas, normal adrenal cortices (NA), non-functional adrenal adenomas (NFA) and cortisol-producing adenomas (CPA). Methods   Total RNA and protein were extracted from 20 CPA, 6 SCS, 15 NFA, and 8 NA. Real-time quantitative polymerase chain reaction (PCR), western blotting and immunohistochemistry analysis were performed to determine the mRNA and protein expression of CYP17 and CYP11B1 in different tissues. Expressions of CYP17 and CYP11B1 in the adrenocortical tumors were compared in NA. Results   Expressions of both CYP11B1 and CYP17 mRNA and protein were detected in all samples tested. Expressions of CYP11B1 mRNA and protein were significantly higher in CPA group than the others, and were slightly higher in SCS samples than that in NA and NFA samples (P<0.05). Expressions of CYP17 mRNA and protein in different tissues were similar to that of CYP11B1. They showed positive correlations with plasma cortisol and negative correlations with adrenocorticotrophin levels (P<0.05). Conclusion   CYP11B1 and CYP17 were over-expressed in subclinical CPA,and their over-expressions were caused by the increased production of cortisol in CPA.

Key words: Adrenocortical tumor； Cortisol； Steroidogenic enzyme； Subclinical Cushing’s syndrome