Growth hormone binding protein and acid labile subunit levels in the assessment of acromegaly treatment.

Abstract

OBJECTIVE: Post-treatment monitoring of acromegalic patients is a matter of controversy, as discrepancies between GH and IGF-I levels have been reported. The aim of our study was to evaluate the role of acid-labile subunit (ALS), a component of the 150 kD IGF-I/IGFBP-3/ALS complex, and the growth hormone binding protein (GHBP) in the follow-up of patients with acromegaly after therapeutic intervention. DESIGN: Forty-one patients with acromegaly, 10 at the time of diagnosis and 31 post therapeutic intervention, were studied. Patients were evaluated by the determination of baseline (fasting) IGF-I, ALS and GHBP and of glucose and GH during OGTT. RESULTS: Significantly lower ALS and higher GHBP levels were detected in successfully treated acromegalics compared to patients before treatment (34.1+/-1.6 vs. 52.8+/-2 mg/L and 0.9+/-0.08 vs 0.4+/-0.1 ìg/L, respectively P<0.05). Furthermore, no difference was noted in ALS and GHBP values between patients successfully treated with either somatostatin analogues or another type of treatment. CONCLUSIONS: a) Successfully treated acromegalic patients demonstrate lower ALS and higher GHBP levels than patients before treatment, and b) somatostatin analogue treatment does not have a direct effect on GHBP and ALS concentration in acromegaly. Studies in larger groups of patients are needed to disclose whether these alterations will be useful in the post-treatment assessment of acromegalic patients.