Expression, Role, and Clinical Implications of P450 Aromatase Enzymes in the Pituitary Gland: A Scoping Review

A BSTRACT The enzyme aromatase (P450AROM) has an important role in the estrogen biosynthesis of several normal tissues. The current scoping review is aimed to review the current literature to understand the expression/localization of P450 and aromatase enzymes in the pituitary, their role in pituitary hormone regulation. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We included in vivo or in vitro experimental studies, observational studies in English and the population was studies on human or animal pituitary tissue or cell lines, intervention/exposure was studies reporting on P450 (CYP2B6, CYP19A1/aromatase), the comparator was healthy versus diseased tissue, normal versus modified expression and the outcome was expression levels, localization, physiological or pathological roles of the enzyme. A total of 380 records were identified and five studies eligible for qualitative synthesis. Aromatase expression in pituitary adenomas was heterogeneous; one study reported a significant positive correlation between aromatase expression and tumor invasiveness ( P < 0.05) in prolactinomas, while another found expression to be nearly absent in adenomatous tissue. Functional analysis demonstrated that aromatase inhibition disrupts negative feedback loops, leading to a marked rise in testosterone ( P < 0.001), while CYP19A1 polymorphisms were found to influence pituitary regulation by altering systemic estradiol levels. Risk of bias assessment showed one low, three moderate, and one high-risk studies. Increased P450AROM expression in prolactinomas in postmenopausal women has been shown to influence tumors invasiveness. In certain subgroups, the expression of ER-b in prolactinoma tissue may be associated with dopamine agonist resistance.