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Exp Clin Endocrinol Diabetes 1998; 106(2): 130-134
DOI: 10.1055/s-0029-1211964
Original

© J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York

Insulin-like growth factor binding protein-3 levels during early and late follow-up after surgery in acromegalic patients

P. Charalampaki1 , G. Hildebrandt1 , H.-J. Schaeffer2 , E. Schönau3 , N. Klug1
  • 1Department of Neurosurgery, University of Cologne, Cologne
  • 2Department of Obstetrics and Gynaecology, University of Cologne, Cologne
  • 3Department of Pediatrics, University of Cologne, Cologne
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Publication Date:
14 July 2009 (online)

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Summary

Disease activity in acromegaly is accurately reflected

by growth hormone (GH) concentration during oral glucose tolerance test (OGTT) and insulin-like growth factor-I (IGF-I) levels, representing an integrated index of GH activity. This prospective study was performed to evaluate whether plasma IGF binding protein 3 (IGFBP-3) might also reflect the hormonal disease activity in pituitary acromegaly after operative treatment during early and late follow-up.

Twenty-two acromegalic patients were studied. Data were obtained pre-, intra- and post-operatively in 13 cases. In 9 patients the acromegalic activity was studied only after treatment. The hormonal assessment included repeated blood samples for estimation of IGF-I, IGFBP-3 and repeated OGTTs.

In each case 100 çg octreotide (SandostatinA, Sandoz, Basel) was injected to test the acute response of GH, IGF-I and IGFBP-3. Intraoperatively, GH levels were estimated to examine acutely the influence of tumour reduction on GH levels. Patients were considered cured when GH levels (GH60min) were less than 2 µg/ml during OGTT 4 weeks after surgery.

The data outlined that in patients with normalized GH60min levels, normalized IGFBP-3 levels were noticed 4 weeks and 12 months post-operatively. In non-cured patients normalized IGFBP-3 concentrations were found in 11 out of 15 cases in the late post-treatment phase. In contrast only 1 of 7 cured patients had persistently elevated IGF-I levels within the first month post-operatively, whereas no case of the non-cured patients had IGF-I values in the normal range. Despite these observations a strong correlation of IGF-I and IGFBP-3 did not exist before one year post-operatively — either in the cured or in the non-cured patients.

Serum IGFBP-3 in patients with pituitary acromegaly does not provide a predictive value of appreciable magnitude concerning cure or non-cure from the disease- whether examined early or late in the post-operative period. Absolute levels of IGFBP-3 may thus cause misinterpretation concerning cure of acromegalics after surgery.

Key words

Pituitary acromegaly - insulin-like growth factor-I - insulin-like growth factor binding protein-3 - late follow-up