Acromegaly: correlation between expression of somatostatin receptor subtypes and response to octreotide-lar treatment.

Abstract

About one-third of acromegalics are resistant to the clinically available somatostatin analogs (SA). The resistance is related to density reduction or different expression of somatostatin receptor subtypes (SSTR). This study analyzes SSTR's expression in somatotrophinomas, comparing to SA response, hormonal levels, and tumor volume. We analyzed 39 somatotrophinomas; 49% were treated with SA. The most expressed SSTR was SSTR5, SSTR3, SSTR2, SSTR1, and SSTR4, respectively. SSTR1 and SSTR2 had higher expression in patients that had normalized GH and IGF-I. SSTR3 was more expressed in patients with tumor reduction. There was a positive correlation between the percentage of tumor reduction and SSTR1, SSTR2 and SSTR3 expression. Also, a positive correlation between SSTR2 mRNA expression and the immunohistochemical reactivity of SSTR2 was found. Our study confirmed the association between the SA response to GH and IGF-I and the SSTR2. Additionally, this finding was also demonstrated in relation to SSTR1.

• Authors: Ana Paula M Casarini, Raquel S Jallad, Emília M Pinto, Iberê C Soares, Suely Nonogaki, Daniel Giannella-Neto, Nina R Musolino, Venâncio A F Alves, Marcello D Bronstein
• Journal: Pituitary (Pituitary) Vol. 12 Issue 4 Pg. 297-303 ( 2009) ISSN: 1573-7403 [Electronic] United States
• PMID: 19330452 (Publication Type: Journal Article)

Chemical References

• Antineoplastic Agents, Hormonal
• Receptors, Somatostatin
• somatostatin receptor 3
• somatostatin receptor subtype-4
• somatostatin receptor type 1
• Human Growth Hormone
• Somatostatin
• Insulin-Like Growth Factor I
• somatostatin receptor 5
• somatostatin receptor 2
• Octreotide

Topics

• Acromegaly (drug therapy, metabolism)
• Antineoplastic Agents, Hormonal (therapeutic use)
• Human Growth Hormone (metabolism)
• Humans
• Immunohistochemistry
• Insulin-Like Growth Factor I (metabolism)
• Octreotide (therapeutic use)
• Receptors, Somatostatin (genetics, metabolism)
• Reverse Transcriptase Polymerase Chain Reaction
• Somatostatin (analogs & derivatives)