Analysis of somatostatin receptors 2 and 5 polymorphisms in patients with acromegaly

Objective: The aim of the study was to investigate the possible correlation of single nucleotide polymorphisms in somatostatin receptor (SSTR)2 and SSTR5 genes with the responsiveness to somatostatin analogs in a cohort of acromegalic patients. Study Design: Three single nucleotide polymorphisms (a-83 g, c-57 g, and t80c) of SSTR2 and three (t-461c, c325t, and c1004t) of SSTR5 were analyzed in 66 acromegalic patients with different responsiveness to somatostatin analogs and 66 healthy controls. Results: Allele frequencies in patients and controls were similar. No association between SSTR2 genotypes and GH and IGF-I levels was found. When considering SSTR5 variants, patients homozygous or heterozygous for the substitution c1004 (P) showed basal IGF-I levels significantly lower than patients homozygous for 1004t (P). Moreover, serum GH levels were lower in patients with P/T haplotype (having c1004 allele and no t-461 allele) than in those with P/T. No correlation between SSTR2 and SSTR5 genotypes, responsiveness to somatostatin therapy, and mRNA expression in the removed adenomas (n 10) was found. Conclusions:ThesedatasuggestaroleforSSTR5t–461candc1004t alleles in influencing GH and IGF-I levels in patients with acromegaly, whereas SSTR2 and SSTR5 variants seem to have a minor role in determining the responsiveness to somatostatin analogs. (J Clin Endocrinol Metab 90: 4824–4828, 2005)