title: Localization of the aromatase enzyme expression in the human pituitary gland and its effect on growth hormone, prolactin, and thyroid stimulating hormone axis.
abstract: The aim of this study is to evaluate aromatase expression in prolactin (PRL), thyroid stimulating hormone (TSH), and growth hormone (GH) secreting cells. Nontumoral human pituitary specimens were obtained from autopsy samples. Aromatase co-expression was determined by double immunohistochemical staining and assessed using H scores. H scores for GH-aromatase co-expression (GH-aromatase), TSH-aromatase co-expression (TSH-aromatase), and PRL-aromatase co-expression (PRL-aromatase) were 83.1 ± 13.1, 95.6 ± 16.1, and 83.7 ± 14.5, respectively. TSH producing cells exhibited the highest H score for co-expression of aromatase (p < 0.001). There was no gender difference in terms of H scores for aromatase expression and double immunohistochemical staining results (p > 0.05 for all). There was a negative correlation between the H scores for aromatase and PRL-aromatase, GH-aromatase and TSH-aromatase, respectively (r = -0.592, p < 0.001; r = -0.593, p < 0.001; r = -0.650, p < 0.001, respectively). Also, H scores for aromatase co-expression of each hormone were negatively correlated with the H scores for the corresponding hormone (r = -0.503, p < 0.001 for PRL-aromatase and PRL; r = -0.470, p < 0.001 for GH-aromatase, and GH; r = -0.641, p < 0.001 for TSH-aromatase and TSH). H scores for mean aromatase, GH-aromatase, TSH-aromatase were invariant of age (p > 0.05 for all). Age was negatively correlated with PRL-aromatase H score (r = -0.373, p = 0.008). Our study demonstrated significant aromatase co-expression in PRL, GH, and TSH secreting cells of the human anterior pituitary gland. The mutual paracrinal regulation between aromatase and three adenohypophyseal hormones indicates that aromatase may have a regulatory role on the synthesis and secretion of these hormones.
authors.affiliation: Endocrinology and Metabolism Department, Cerrahpasa Medical School, University of Istanbul, 34303, Cerrahpasa, Istanbul, Turkey.
authors.forename: Asli Sezgin
authors.initials: AS
authors.lastname: Caglar
authors.forename: Aysegul
authors.initials: A
authors.lastname: Kapucu
authors.forename: Kadriye Akgun
authors.initials: KA
authors.lastname: Dar
authors.forename: Hande Mefkure
authors.initials: HM
authors.lastname: Ozkaya
authors.forename: Erkan
authors.initials: E
authors.lastname: Caglar
authors.forename: Haluk
authors.initials: H
authors.lastname: Ince
authors.forename: Pinar
authors.initials: P
authors.lastname: Kadioglu
mesh_terms: D000328:Adult; D001141:Aromatase / Q000096:biosynthesis*; D002102:Cadaver; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010902:Pituitary Gland / Q000201:enzymology*; D011388:Prolactin / Q000378:metabolism*; D013972:Thyrotropin / Q000378:metabolism*
chemical_list: D019382:Human Growth Hormone; D011388:Prolactin; D013972:Thyrotropin; D001141:Aromatase; C561410:CYP19A1 protein, human