title: The transcription activator steroidogenic factor-1 is preferentially expressed in the human pituitary gonadotroph.
abstract: Steroidogenic factor-1 (SF-1), also known as adrenal-4-binding protein, is a transcription factor that is important for the differentiation of steroidogenic tissues. We investigated whether SF-1 is expressed in specific hormone-producing cell types in the human pituitary and its adenomas. Pituitary adenomas (n = 35) were collected at the time of surgery, and normal adenohypophyses were obtained from autopsies; 3 corticotroph adenomas were excluded because pit-1 messenger ribonucleic acid (mRNA) expression indicated contamination by nontumorous elements. Expression of SF-1 mRNA was determined by reverse transcription-PCR. SF-1 protein was localized with immunocytochemistry. By reverse transcription-PCR, SF-1 mRNA was found in the nontumorous pituitary and in pituitary adenomas expressing gonadotropins. All 8 gonadotroph adenomas had a strong signal for SF-1. SF-1 mRNA was also detected in 2 of 3 corticotroph adenomas, 2 of 13 somatotroph/mammosomatotroph adenomas, 1 of 6 lactotroph adenomas, and 2 silent subtype 3 adenomas; however, in most of the positive tumors there was also positivity for FSH beta and/or LH beta mRNA, suggesting that contaminating nontumorous gonadotrophs may be the source of SF-1 mRNA signal. SF-1 protein was localized by immunocytochemistry in the nuclei of scattered cells of the nontumorous adenohypophysis that were shown to be gonadotrophs with double immunostaining and in gonadotroph adenomas; nuclear staining was not found in other adenoma types, except in areas shown to contain trapped nontumorous tissue. We conclude that SF-1 expression correlates with the expression of gonadotropins. These findings implicate SF-1 as a cell-specific transcription factor that may regulate gonadotroph differentiation in the pituitary.
authors.affiliation: Department of Pathology, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: S L
authors.initials: SL
authors.lastname: Asa
authors.forename: A M
authors.initials: AM
authors.lastname: Bamberger
authors.forename: B
authors.initials: B
authors.lastname: Cao
authors.forename: M
authors.initials: M
authors.lastname: Wong
authors.forename: K L
authors.initials: KL
authors.lastname: Parker
authors.forename: S
authors.initials: S
authors.lastname: Ezzat
mesh_terms: D000236:Adenoma / Q000378:metabolism / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D051717:Fushi Tarazu Transcription Factors; D006062:Gonadotropins / Q000378:metabolism*; D018398:Homeodomain Proteins; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000378:metabolism / Q000473:pathology; D016133:Polymerase Chain Reaction; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014018:Tissue Distribution; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D006062:Gonadotropins; D018398:Homeodomain Proteins; C515057:NR5A1 protein, human; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014157:Transcription Factors