Expression of an orphan nuclear receptor DAX-1 in human pituitary adenomas.
OBJECTIVE
An orphan nuclear receptor, DAX-1, is known to be involved in the development and differentiation of anterior pituitary cells. The present study aimed to examine 1) whether DAX-1 is expressed in human pituitary adenomas, and 2) if it is expressed, what types of adenoma express the factor.


METHODS
Adenoma tissues examined included 18 clinically non-functioning adenomas, 14 GH-secreting adenomas and 7 PRL-secreting adenomas. The expression of the following genes were tested by reverse transcription-polymerase chain reaction (RT-PCR): DAX-1, Adrenal-4-binding protein/steroidogenic factor-1 (Ad4BP/SF-1), Pit-1, LH beta, FSH beta, gonadotrophin-releasing hormone receptor (GnRH-R), GH, PRL, and TSH beta, as well as beta-actin as a control.


RESULTS
Eleven clinically non-functioning adenomas expressed DAX-1, 10 of which also expressed Ad4BP/SF-1. Nine out of the 11 DAX-1 expressing adenomas also expressed LH beta, FSH beta and GnRH-R as well, indicating that these adenomas possessed gonadotrophic properties. Nine clinically non-functioning adenomas expressed Pit-1 as well as GH, PRL and/or TSH beta, thus having somatomammotrophic or thyrotrophic properties, 3 of which overlapped with the above DAX-1-expressing adenomas. One non-functioning adenoma expressed Ad4BP/SF1 and FSH beta but not DAX-1, and another one expressed DAX-1 and Ad4BP/SF-1 with PRL. On the other hand, all GH-secreting and PRL-secreting adenomas expressed Pit-1 and GH and/or PRL, but neither DAX-1 nor Ad4BP/SF-1.


CONCLUSIONS
The results shown here indicate that DAX-1 is expressed in the majority of human pituitary adenomas of gonadotrophic origin in parallel with Adrenal-4-binding protein/steroidogenic factor-1.
Third Department of Internal Medicine, Kyushu University Faculty of Medicine, Fukuoka, Japan.
S
S
Ikuyama
Y M
YM
Mu
K
K
Ohe
H
H
Nakagaki
T
T
Fukushima
R
R
Takayanagi
H
H
Nawata
D000236:Adenoma / Q000378:metabolism*; D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins / Q000235:genetics*; D005640:Follicle Stimulating Hormone / Q000235:genetics; D037201:Follicle Stimulating Hormone, beta Subunit; D015870:Gene Expression; D013006:Growth Hormone / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007986:Luteinizing Hormone / Q000235:genetics; D010911:Pituitary Neoplasms / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011388:Prolactin / Q000235:genetics; D015175:Prolactinoma / Q000378:metabolism; D011966:Receptors, LHRH / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000235:genetics*; D012097:Repressor Proteins; D013972:Thyrotropin / Q000235:genetics; D050817:Transcription Factor Pit-1; D014157:Transcription Factors / Q000235:genetics*
D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins; D037201:Follicle Stimulating Hormone, beta Subunit; C539965:NR0B1 protein, human; C494187:POU1F1 protein, human; D011966:Receptors, LHRH; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D050817:Transcription Factor Pit-1; D014157:Transcription Factors; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013972:Thyrotropin; D013006:Growth Hormone