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- Title
Growth hormone receptor expression and function in pituitary adenomas.
- Authors
Clausen, Lene R.; Kristiansen, Mikkel T.; Rasmussen, Lars M.; Billestrup, Nils; Blaabjerg, Ole; Ledet, Thomas; Jørgensen, Jens O. L.
- Abstract
OBJECTIVE AND DESIGN: Hypopituitarism, in particular GH deficiency, is prevalent in patients with clinically nonfunctioning pituitary adenomas (NFPAs) both before and after surgery. The factors regulating the growth of pituitary adenomas in general and residual tumour tissue in particular are not fully characterized, and the effect of GH and IGF-l on human pituitary cell proliferation has not previously been reported. In NFPA tissue from 14 patients we evaluated GH receptor (GHR) expression and signal transduction, and the effect of GH and IGF-l exposure on cell proliferation and hormone secretion in vitro. MEASUREMENTS: Tissue samples from 14 NFPAs were investigated. Expression of GHR in tissue samples was assessed by reverse transcription polymerase chain reaction (RT-PCR). Six tumours were immuno-stained with a GHR antibody. In the cell cultures, STATS (signal transducer and activator of transcription 5) phosphorylation was measured by Western blot analysis as an index of GHR signalling; cell proliferation was evaluated by [H³]-thymidine incorporation and glycoprotein hormone production analysed by radio-immunoassay (RIA). RESULTS: All adenomas investigated expressed the GHR, but there was no detection of STATS phosphorylation. Overall, GH and IGF-l administration did not significantly stimulate cell proliferation in vitro, although some individual adenomas exhibited a proliferative response to various extents. GH also did not significantly influence glycoprotein hormone secretion In vitro. CONCLUSION: GH receptors are expressed in human pituitary adenoma cells but their functional role is uncertain. GH and IGF-l do not consistently influence the proliferation of cultured pituitary adenoma cells.
- Subjects
PITUITARY hormones; SOMATOTROPIN; SHEEHAN'S syndrome; PUERPERAL disorders; IMMUNOGLOBULINS; PHOSPHORYLATION
- Publication
Clinical Endocrinology, 2004, Vol 60, Issue 5, p576
- ISSN
0300-0664
- Publication type
Article
- DOI
10.1111/j.1365-2265.2004.02022.x