Expression analysis of dopamine receptor subtypes in normal human pituitaries, nonfunctioning pituitary adenomas and somatotropinomas, and the association between dopamine and somatostatin receptors with clinical response to octreotide-LAR in acromegaly.

Context: Dopamine receptor (DR) and somatostatin receptor subtype expression in pituitary adenomas may predict the response to postsurgical therapies.

Objectives: Our objectives were to assess and compare the mRNA levels of DR1-5 and somatostatin receptors 1-5 in normal pituitaries (NPs), nonfunctioning pituitary adenomas (NFPAs), and somatotropinomas. In addition, we determined whether the level of DR expression correlates with the in vivo response to octreotide-LAR in acromegalic patients.

Quantitative analysis of somatostatin receptor subtypes (1-5) gene expression levels in somatotropinomas and correlation to in vivo hormonal and tumor volume responses to treatment with octreotide LAR.

Objective: To determine whether the somatostatin receptor subtype (SSTR) expression profile correlates with hormonal and tumor volume responses to postsurgical octreotide long acting repeatable (OCT LAR) treatment.

Design And Methods: Quantitative real-time RT-PCR was used to evaluate the absolute mRNA copy numbers for all five SSTR subtypes in 22 somatotropinomas. Response to OCT LAR was studied by hormone levels (GH and IGF-I) and tumor volume (sella turcica magnetic resonance imaging).

Quantitative analysis of somatostatin receptor subtype (SSTR1-5) gene expression levels in somatotropinomas and non-functioning pituitary adenomas.

Objective: It is believed that the variable effectiveness of somatostatin analogs in post-surgical management of somatotropinomas and non-functioning pituitary adenomas (NFPA) may be due in part to variable expression of somatostatin receptor isoforms (SSTR1-5), within and between pituitary tumor types.

Design And Methods: Quantitative real-time RT-PCR was used to compare absolute mRNA copy numbers for all five SSTR isoforms in 23 somatotropinomas and 19 NFPA.

Results: Somatostatin receptor subtype 5 mRNA was present at the highest level in somatotropinomas, followed by SSTR2>SSTR3>>SSTR1>>>SSTR4.