The mimecan gene expressed in human pituitary and regulated by pituitary transcription factor-1 as a marker for diagnosing pituitary tumors.
BACKGROUND
Mimecan, a secretory protein, belongs to a family of small leucine-rich proteoglycans (SLRPs). The physiological functions of mimecan have not been fully understood.


OBJECTIVE
We hypothesize that the mimecan gene expressed in the human pituitary and regulated by pituitary transcription factor-1 (Pit-1) might act as a marker for diagnosing pituitary tumors.


METHODS
The clinical aspect of our work was a cross-sectional study.


METHODS
In total, 20 pituitary tumor samples were collected from January 1, 2002, to December 30, 2002, in Ruijin Hospital, Shanghai, China.


METHODS
The number of pituitary tumors was limited. Collection of more pituitary tumor samples for additional observation will be necessary.


METHODS
The main outcomes were measured by Northern blot, in situ hybridization, immunohistochemical analysis, and so on.


RESULTS
The mimecan gene was expressed at a moderate level in the mouse pituitary gland by Northern blot analysis. Expression of mimecan mRNA and protein is also observed in the human anterior pituitary gland. Luciferase reporter analysis and electrophoretic mobility shift assays show that Pit-1 activates the human mimecan promoter through Pit-1 response element sites. In addition, our data also show that almost all the ACTH- or GH-positive pituitary tumors likely express mimecan protein, and only a portion of prolactin-, TSH-, FSH-, and LH-positive pituitary tumors express mimecan protein.


CONCLUSIONS
This work provides insight into the regulating mechanism of mimecan in pituitary and suggests that mimecan may be an unidentified pituitary secretory protein, and certain pituitary cells secreting ACTH or GH also secrete mimecan.
Hu
San-Mei
SM
Ruijin Hospital, State Key Laboratory of Medical Genomics, Shanghai Second Medical University, Shanghai, China, 200025.
Li
Feng
F
Yu
Hui-Min
HM
Li
Rong-Ying
RY
Ma
Qin-Yun
QY
Ye
Ting-Jun
TJ
Lu
Zhen-Yu
ZY
Chen
Jia-Lun
JL
Song
Huai-Dong
HD
D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002460:Cell Line; D003430:Cross-Sectional Studies; D005786:Gene Expression Regulation; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D010902:Pituitary Gland / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020218:Response Elements; D050817:Transcription Factor Pit-1 / Q000502:physiology*; D014158:Transcription, Genetic / Q000502:physiology
D014408:Biomarkers, Tumor; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; C063488:OGN protein, human; C512906:Ogn protein, mouse; D050817:Transcription Factor Pit-1