Peroxisome Proliferator Activated Receptor γ Expression Is Reduced in the Colonic Mucosa of Acromegalic Patients

Acromegalic patients have an increased prevalence of colonic polyps, due to the elevated serum insulin like growth factor (IGF)-I levels. The mechanisms underlying this process are poorly understood. Peroxisome proliferator activated receptor (PPAR)γ, a nuclear receptor that regulates adipocyte differentiation, is highly expressed in the human colonic mucosa, where it induces growth inhibition and cell differentiation. In the present study we evaluated the expression of PPARγ in the bioptic samples of colonic mucosa from 22 patients with acromegaly (Acro) and 13 normal subjects (Controls) matched for age and sex. Among Acro patients, 10 had active, untreated disease (AcroUntr), 6 were in remission after surgery (AcroRem), and 6 had active disease under treatment with somatostatin analogs (AcroSMSa). Serum GH and IGF-I (mean ± SD) levels were as follows: AcroUntr: GH, 36 ± 40 μg/l; IGF-I, 769 ± 298 μg/l; AcroRem: GH, 1.0 ± 1.3μ g/l; IGF-I, 248 ± 96 μg/l; AcroSMSa: GH, 7.8 ± 12 μg/l; IGF-I, 429 ± 221 μg/l; ...