Journal of Clinical Endocrinology & Metabolism, Vol 80, 2933-2939, Copyright © 1995 by Endocrine Society

ARTICLES

Identification of alternatively spliced messenger ribonucleic acid encoding truncated growth hormone-releasing hormone receptor in human pituitary adenomas

K Hashimoto, M Koga, T Motomura, S Kasayama, H Kouhara, T Ohnishi, N Arita, T Hayakawa, B Sato and T Kishimoto
Department of Medicine III, Osaka University Medical School, Japan.

The expression of GHRH receptor (GHRH-R) messenger ribonucleic acid (mRNA) was studied in 22 pituitary adenomas and 2 normal anterior pituitaries. Northern blot analysis revealed that GHRH-R mRNA were expressed in all 14 GH-producing adenomas, 1 of 3 ACTH-producing adenomas, the 1 PRL-producing adenoma, 2 of 4 nonfunctioning adenomas, and the 2 normal anterior pituitaries. Their expression levels varied among GH-producing adenomas and were relatively low in GH-nonproducing adenomas. In addition to the major transcript with a molecular mass of 2.0 kilobases (kb), the transcripts were identified at 2.8 and 4.5 kb in some GH-producing adenomas. To examine the structural variations in GHRH-R mRNA in pituitary adenomas, we amplified the complementary DNA fragment encompassing the region from the third cytoplasmic loop to the sixth transmembrane domain of GHRH-R. This region was selected because this region of the G protein-coupled receptor has been known to interact with G protein. Two amplified fragments with the molecular masses of 250 and 810 base pairs were identified by the reverse transcriptase-polymerase chain reaction method. The nucleotide sequence of a smaller fragment, which was the expected size, revealed that no mutations were found in this region in 10 GH-producing adenomas examined. However, a larger fragment contained the currently unidentified insertion. Compared with the genomic DNA sequence, this insertion was found to be generated through alternative splicing. In addition, this variant form contained the premature stop codon in- frame, indicating that it encodes the truncated GHRH-R. This insertion- specific probe could hybridize with 2.8- and 4.5-kb species of GHRH-R mRNA on Northern blot analysis, and these transcripts were expressed mainly in GH-producing adenomas. Finally, study of cell transfection and cAMP measurement revealed that this truncated GHRH-R was unable to transmit GHRH signals. These results suggest that some GH-producing adenomas preferentially express the truncated GHRH-R as a nonfunctioning receptor through alternative splicing.

This article has been cited by other articles:

				K. Bedard, J. Strecko, K. Theriault, J. Bedard, C. Veyrat-Durebex, and P. Gaudreau Effects of a high-glucose environment on the pituitary growth hormone-releasing hormone receptor: type 1 diabetes compared with in vitro glucotoxicity Am J Physiol Endocrinol Metab, April 1, 2008; 294(4): E740 - E751. [Abstract] [Full Text] [PDF]

				C. Y. Wang, Y. Wang, A. H. Y. Kwok, and F. C Leung Identification of two novel chicken GHRH receptor splice variants: implications for the roles of aspartate 56 in the receptor activation and direct ligand receptor interaction J. Endocrinol., December 1, 2007; 195(3): 525 - 536. [Abstract] [Full Text] [PDF]

				A. T. McElvaine and K. E. Mayo A Dominant-Negative Human Growth Hormone-Releasing Hormone (GHRH) Receptor Splice Variant Inhibits GHRH Binding Endocrinology, April 1, 2006; 147(4): 1884 - 1894. [Abstract] [Full Text] [PDF]

				A. P. Heaney Pituitary tumour pathogenesis. Br. Med. Bull., January 1, 2006; 75-76: 81 - 97. [Abstract] [Full Text] [PDF]

				G. L. Toller, J. E. Horvath, A. V. Schally, G. Halmos, J. L. Varga, K. Groot, D. Chism, and M. Zarandi Development of a polyclonal antiserum for the detection of the isoforms of the receptors for human growth hormone-releasing hormone on tumors PNAS, October 19, 2004; 101(42): 15160 - 15165. [Abstract] [Full Text] [PDF]

				K. E. Mayo, L. J. Miller, D. Bataille, S. Dalle, B. Goke, B. Thorens, and D. J. Drucker International Union of Pharmacology. XXXV. The Glucagon Receptor Family Pharmacol. Rev., March 1, 2003; 55(1): 167 - 194. [Abstract] [Full Text] [PDF]

				C. Boisvert, C. Pare, C. Veyrat-Durebex, A. Robert, S. Dubuisson, G. Morel, and P. Gaudreau Localization and Regulation of a Functional GHRH Receptor in the Rat Renal Medulla Endocrinology, April 1, 2002; 143(4): 1475 - 1484. [Abstract] [Full Text] [PDF]

				A. Peri, B. Conforti, S. Baglioni-Peri, P. Luciani, F. Cioppi, L. Buci, S. Corbetta, E. Ballaré, M. Serio, and A. Spada Expression of Cyclic Adenosine 3',5'-Monophosphate (cAMP)-Responsive Element Binding Protein and Inducible-cAMP Early Repressor Genes in Growth Hormone-Secreting Pituitary Adenomas with or without Mutations of the Gs{{alpha}} Gene J. Clin. Endocrinol. Metab., May 1, 2001; 86(5): 2111 - 2117. [Abstract] [Full Text]

				H. G. Maheshwari, T. R. Prezant, V. Herman-Bonert, H. Shahinian, K. Kovacs, and S. Melmed Long-Acting Peptidomimergic Control of Gigantism Caused by Pituitary Acidophilic Stem Cell Adenoma J. Clin. Endocrinol. Metab., September 1, 2000; 85(9): 3409 - 3416. [Abstract] [Full Text]

				Z. Rekasi, J. L. Varga, A. V. Schally, G. Halmos, P. Armatis, K. Groot, and T. Czompoly Antagonists of Growth Hormone-Releasing Hormone and Vasoactive Intestinal Peptide Inhibit Tumor Proliferation by Different Mechanisms: Evidence from in Vitro Studies on Human Prostatic and Pancreatic Cancers Endocrinology, June 1, 2000; 141(6): 2120 - 2128. [Abstract] [Full Text] [PDF]

				T. L. Miller, P. A. Godfrey, V. I. DeAlmeida, and K. E. Mayo The Rat Growth Hormone-Releasing Hormone Receptor Gene: Structure, Regulation, and Generation of Receptor Isoforms with Different Signaling Properties Endocrinology, September 1, 1999; 140(9): 4152 - 4165. [Abstract] [Full Text]

				T. J. Baranski, P. Herzmark, O. Lichtarge, B. O. Gerber, J. Trueheart, E. C. Meng, T. Iiri, S. P. Sheikh, and H. R. Bourne C5a Receptor Activation. GENETIC IDENTIFICATION OF CRITICAL RESIDUES IN FOUR TRANSMEMBRANE HELICES J. Biol. Chem., May 28, 1999; 274(22): 15757 - 15765. [Abstract] [Full Text] [PDF]

				A. Giustina and J. D. Veldhuis Pathophysiology of the Neuroregulation of Growth Hormone Secretion in Experimental Animals and the Human Endocr. Rev., December 1, 1998; 19(6): 717 - 797. [Abstract] [Full Text]

				S. L. Asa and S. Ezzat The Cytogenesis and Pathogenesis of Pituitary Adenomas Endocr. Rev., December 1, 1998; 19(6): 798 - 827. [Abstract] [Full Text]

				V. I. DeAlmeida and K. E. Mayo Identification of Binding Domains of the Growth Hormone-Releasing Hormone Receptor by Analysis of Mutant and Chimeric Receptor Proteins Mol. Endocrinol., May 1, 1998; 12(5): 750 - 765. [Abstract] [Full Text]

				S. Petersenn, A. C. Rasch, M. Heyens, and H. M. Schulte Structure and Regulation of the Human Growth Hormone-Releasing Hormone Receptor Gene Mol. Endocrinol., February 1, 1998; 12(2): 233 - 247. [Abstract] [Full Text]

				N. Sanno, A. Teramoto, R. Y. Osamura, S. Genka, H. Katakami, L. Jin, R. V. Lloyd, and K. Kovacs A Growth Hormone-Releasing Hormone-Producing Pancreatic Islet Cell Tumor Metastasized to the Pituitary Is Associated with Pituitary Somatotroph Hyperplasia and Acromegaly J. Clin. Endocrinol. Metab., August 1, 1997; 82(8): 2731 - 2737. [Abstract] [Full Text] [PDF]

				I. Shimon and S. Melmed Pituitary Tumor Pathogenesis J. Clin. Endocrinol. Metab., June 1, 1997; 82(6): 1675 - 1681. [Full Text] [PDF]

				Z. Rekasi, T. Czompoly, A. V. Schally, and G. Halmos Isolation and sequencing of cDNAs for splice variants of growth hormone-releasing hormone receptors from human cancers PNAS, September 12, 2000; 97(19): 10561 - 10566. [Abstract] [Full Text] [PDF]