title: Loss of growth hormone secretagogue receptor 1a and overexpression of type 1b receptor transcripts in human adrenocortical tumors.
abstract: OBJECTIVE
  Quantitative analysis of mRNA expression of ghrelin and its receptors GHS-R1a and -R1b in a large series of normal and neoplastic human adrenocortical tissues. Evaluation of the effects of ghrelin on GHS-R expression and proliferation of human adrenocortical carcinoma (ACC) cell lines.
  
  
  RESULTS
  Ghrelin and GHS-R transcripts are expressed in normal adrenal cortex, with GHS-R1b mRNA levels being 5- to 10-fold higher than GHS-R1amRNA. A significant increase in ghrelin expression was observed in adrenocortical adenomas, but not in carcinomas. GHS-R1a was undetectable in about 60% of both benign and malignant tumor samples, except for cortisol-producing adenomas, which showed increased receptor expression. At variance, GHS-R1b was overexpressed in both benign and malignant adrenocortical tumors. In vitro studies in human ACC cell lines demonstrated that GHS-R1a is downregulated and GHS-R1bmRNA expression is upregulated by ghrelin, while inhibiting cell proliferation.
  
  
  CONCLUSIONS
  Downregulation ofGHS-R1a in adrenal tumors and the presence of high levels of GHS-R1b transcripts in adrenocortical tissue suggest a role for these receptors in adrenal function and growth. In this regard, ghrelin inhibits cell proliferation and modulates GHS-R expression in ACC cells in vitro.
authors: Department of Histology, Microbiology and Medical Biotechnologies, University of Padova, Padova, Italy. luisa.barzon@unipd.it
authors: Luisa
authors: L
authors: Barzon
authors: Monia
authors: M
authors: Pacenti
authors: Giulia
authors: G
authors: Masi
authors: Anna-Lisa
authors: AL
authors: Stefani
authors: Karina
authors: K
authors: Fincati
authors: Giorgio
authors: G
authors: Palù
mesh_terms: D000302:Adrenal Cortex / Q000378:metabolism; D000306:Adrenal Cortex Neoplasms / Q000235:genetics / Q000378:metabolism*; D018246:Adrenocortical Adenoma / Q000235:genetics / Q000378:metabolism*; D018268:Adrenocortical Carcinoma / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D015972:Gene Expression Regulation, Neoplastic; D054439:Ghrelin; D013006:Growth Hormone / Q000494:pharmacology; D006801:Humans; D036361:Peptide Hormones / Q000494:pharmacology; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D054440:Receptors, Ghrelin; D014407:Tumor Cells, Cultured
chemical_list: D054439:Ghrelin; D036361:Peptide Hormones; D010455:Peptides; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D054440:Receptors, Ghrelin; D013006:Growth Hormone