Glucose metabolism alterations in acromegaly
Maria Rosaria Ambrosio, Alessandra Malaspina, Grazia De Paola, Marta Bondanelli, Maria Chiara Zatelli & Ettore degli Uberti
Glucose metabolism alterations are frequently observed in acromegalic patients. Somatostatin analogues (SSTA) are the most widely used drugs to treat acromegaly, since they inhibit GH and IGF-1 levels, reduce pituitary mass, but can affect glucose metabolism. Aim of our study was to evaluate glucose metabolism alterations in acromegalic patients cured after surgery and in patients with active disease during treatment with SSTA. We studied 10 patients (group A, 5F, 55.66±10.83 years, BMI=27.53±5.11 kg/m2) who undergone transphenoidal surgery with disease remission (GH<1 μg/l after OGTT, normal sex and age matched IGF-1 levels) and 10 patients (group B, 6F, 44.88±14.69 years, BMI=27.16±4.43 kg/m2) with active disease, treated with SSTA. We measured at baseline and 12 months after medical o surgical therapy, GH and IGF-1 levels, fasting and post-load (OGTT) glucose and insulin levels, also evaluating the area under the curve (AUC). At baseline, 44.4% of patients had impaired glucose tolerance and l′11.1% diabetes mellitus. No significant differences were observed in GH and IGF-1 levels between the two groups. At 12 months group A patients had normal GH and sex and age matched IGF-1 levels. Fasting and post-load glucose levels, fasting insulin levels and glucose AUC values were significantly reduced (P<0.05) compared to baseline. On the contrary, post OGTT insulin secretion and insulin AUC did not change. In group B, GH and IGF-1 levels, insulin peak during OGTT, and insulin AUC were significantly reduced (P<0.05) compared to baseline. Fasting and post-OGTT glucose levels did not change. Our results confirm that glucose metabolism alterations are frequently observed in active acromegaly. In acromegalic patients with disease remission, an improvement of fasting glucose and insulin levels is observed, likely due to reduction in GH and IGF-1 levels. Therapy with SSTA controls GH and IGF-1 excess, but impairs insulin secretion.