title: Thyrotrophin receptor protein expression in normal and adenomatous human pituitary.
abstract: Thyrotrophin (TSH) synthesis and secretion is under the positive control of thyrotrophin releasing hormone and under the negative control of the thyroid hormones. However, it is hypothesised that TSH has a direct effect on the regulation of its own synthesis through an intrapituitary loop mediated by pituitary TSH receptors (TSH-R). The aim of this investigation was to study the expression of TSH-R in normal human pituitary at mRNA and protein levels, and to compare the pattern of protein expression between different pituitary adenomas. Using RT-PCR we were able to detect TSH-R mRNA in the normal pituitary, and immunohistochemical studies showed TSH-R protein expression in distinct areas of the anterior pituitary. Double immunostaining with antibodies against each of the intrapituitary hormones and S100 revealed that TSH-R protein is present in thyrotrophs and folliculostellate cells. Examination of 58 pituitary adenomas, including two clinically active and two clinically inactive thyrotroph adenomas, revealed TSH-R immunopositivity in only the two clinically inactive thyrotroph adenomas. This study shows, for the first time, the presence of TSH-R protein in the normal anterior pituitary and in a subset of thyrotroph adenomas. The expression of TSH-R in the thyrotroph and folliculostellate cell subpopulations provides preliminary evidence of a role for TSH in autocrine and paracrine regulatory pathways within the anterior pituitary gland.
authors.affiliation: Max-Planck Institute of Psychiatry, Department of Endocrinology, Munich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Theodoropoulou
authors.forename: T
authors.initials: T
authors.lastname: Arzberger
authors.forename: Y
authors.initials: Y
authors.lastname: Gruebler
authors.forename: Z
authors.initials: Z
authors.lastname: Korali
authors.forename: P
authors.initials: P
authors.lastname: Mortini
authors.forename: W
authors.initials: W
authors.lastname: Joba
authors.forename: A E
authors.initials: AE
authors.lastname: Heufelder
authors.forename: G K
authors.initials: GK
authors.lastname: Stalla
authors.forename: L
authors.initials: L
authors.lastname: Schaaf
mesh_terms: D000236:Adenoma / Q000378:metabolism*; D000818:Animals; D018929:Cell Culture Techniques; D000242:Cyclic AMP / Q000096:biosynthesis; D015870:Gene Expression; D006801:Humans; D007124:Immunoenzyme Techniques; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011989:Receptors, Thyrotropin / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013972:Thyrotropin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D009363:Neoplasm Proteins; D012333:RNA, Messenger; D011989:Receptors, Thyrotropin; D013972:Thyrotropin; D000242:Cyclic AMP