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....
Citation
Xu T, Ye F, Wang B, Tian C, Wang S, Shu K, Guo D, Lei T. Elevation of growth hormone secretagogue receptor type 1a mRNA expression in human growth hormone-secreting pituitary adenoma harboring G protein alpha subunit mutation. Neuro Endocrinol Lett. 2010 Jan; 31(1): 147-154