Expression Of Steroidogenic Enzyme In Subclinical Cushing’s Syndrome Due To Adrenal Adenomas

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 CYP17and CYP11B1in SCS adenomas, normal adrenal cortices (NA), non-functional adrenal adenomas (NFA) and cortisol-producing adenomas (CPA).Methods:Total RNA and protein were extracted from20CPA,6SCS,15NFA, and8NA. Real-time quantitative polymerase chain reaction (PCR), western blotting and immunohistochemistry analysis were performed to determine the mRNA and protein expression of CYP17and CYP11B1in different tissues. The expression of CYP17and CYP11B1in the adrenocortical tumors was compared expression in NA.Results:Expressions of both CYP11B1and CYP17mRNA and protein were detected in all samples tested. Expressions of CYP11B1mRNA 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). There was no significant difference in CYP11B1mRNA and protein expression between NA and NFA samples (P>0.05). Expressions of CYP17mRNA and protein in different tissues were similar to that of CYP11B1. Both CYP11B1and CYP17mRNA and protein expressions were correlated with plasma cortisol and adrenocorticotrophin levels (P<0.05).Conclusions:CYP11B1and CYP17were overexpressed in subclinical CPA,and their overexpressions were caused by the increased production of cortisol in CPA.