Elevation of growth hormone secretagogue receptor type 1a mRNA expression in human growth hormone-secreting pituitary adenoma harboring G protein alpha subunit mutation.
OBJECTIVE
The purpose of this study was to investigate the relationship between the ghrelin or GHSR-1a mRNA levels and clinical characteristics and to confirm the effect of gsp mutations on ghrelin/GHSR-1a system in human GH-secreting pituitary adenomas.


METHODS
The expression levels of ghrelin, GHSR-1a mRNA were determined by SYBR green real-time fluorescent quantitative PCR. The gsp mutations in 43 cases of human GH-secreting pituitary adenomas were detected using PCR-DNA direct sequencing analysis. Clinical data were obtained from the medical records of 43 acromegalic patients who had GH and IGF-1 assays in the same laboratory.


RESULTS
The expression of GHSR-1a correlated positvely with tumor size (R=0.411, p=0.006) and invasiveness (p<0.05). In contrast, ghrelin mRNA levels correlated positively only with tumor size (R=0.331, p=0.030) but not with tumor invasiveness (p>0.05). The expression level of GHSR-1a mRNA was significantly higher in gsp positive adenomas than in negative adenomas (p<0.05). Whereas, there was no significant difference in the expression of ghrelin mRNA between gsp mutation-positive and -negative adenomas (p>0.05). Additionally there was a significant positve correlation between the ghrelin and GHSR-1a mRNA expression levels in gsp-positive (R=0.553, p=0.040) or -negative adenomas (R=0.489, p=0.007).


CONCLUSIONS
GHSR-1a correlated positively with tumor size and invasiveness, while ghrelin correlated positively only with tumor size. Gsp mutations may upregulate the expression of GHSR-1a mRNA and have no effect on ghrelin mRNA levels in human GH-secreting pituitary adenomas.
Xu
Tongjiang
T
Department of Neurosurgery, Tongji HospitalTongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Ye
Fei
F
Wang
Baofeng
B
Tian
Chunlei
C
Wang
Sheng
S
Shu
Kai
K
Guo
Dongsheng
D
Lei
Ting
T
D000172:Acromegaly / Q000209:etiology / Q000235:genetics; D000236:Adenoma / Q000150:complications / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D000328:Adult; D005260:Female; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics*; D054439:Ghrelin / Q000235:genetics / Q000378:metabolism; D049912:Growth Hormone-Secreting Pituitary Adenoma / Q000150:complications / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D012333:RNA, Messenger / Q000378:metabolism; D054440:Receptors, Ghrelin / Q000235:genetics* / Q000378:metabolism; D012189:Retrospective Studies; D047368:Tumor Burden; D015854:Up-Regulation; D055815:Young Adult
D044385:GTP-Binding Protein alpha Subunits; D054439:Ghrelin; D012333:RNA, Messenger; D054440:Receptors, Ghrelin