Artículos de revistas
Association between tumoral GH-releasing peptide receptor type 1a mRNA expression and in vivo response to GH-releasing peptide-6 in ACTH-dependent Cushing`s syndrome patients
Fecha
2008Registro en:
EUROPEAN JOURNAL OF ENDOCRINOLOGY, v.158, n.5, p.605-613, 2008
0804-4643
10.1530/EJE-07-0659
Autor
MACHADO, Marcio Carlos
SA, Sandra Valeria de
CORREA-GIANNELLA, Maria Lucia
GIORGI, Ricardo Rodrigues
PEREIRA, Maria Adelaide Albergaria
CESCAT, Valter Angelo S
GIANNELLA-NETO, Daniel
SALGADO, Luiz Roberto
Institución
Resumen
Objective: GH secretagogues (GHS) produce exaggerated ACTH and cortisol responses in Cushing`s disease (CD) patients, attributable to their direct action on GH-releasing peptide receptor type la (GHSR-1a). However, there are no studies correlating the ill vivo response to GHS and GHSR-1a mRNA expression in ACTH-dependent Cushing`s syndrome (CS) patients. The aim of this study is to correlate the patterns of ACTH and cortisol response to GH-releasing peptide-6 (GHRP-6) to GHSR-1a expression in ACTH-dependent CS patients Design: Prospective study in a tertiary referral hospital center. Fifteen CD patients and two ectopic ACTH syndrome (EAS) patients were studied. Methods: Tumor fragments were submitted to RNA extraction, and GHSR-1a expression was studied through real-time qPCR and compared with normal tissue samples. The patients were also submitted to desmopressin test and vasopressin receptor type 1B (AVPR1B) mRNA analysis by qPCR. Results: GHSR-1a expression was similar in normal pituitary samples and in corticotrophic tumor samples. GHSR-1a expression was higher in patients (CD and EAS) presenting ill vivo response to GHRP-6. Higher expression of AVPR1B was observed in the EAS patients responsive to desmopressin, as well as in corticotrophic tumors, as compared with normal pituitary samples, but no correlation between AVPR1B expression and response to desmopressin was observed in the CD patients. Conclusions: Our results revealed a higher expression of GHSR-1a in the ACTH-dependent CS patients responsive to GHRP-6, suggesting an association between receptor gene expression and ill vivo response to the secretagogue in both the CD and the EAS patients.