Increased cortical bone content of insulin-like growth factors in acromegalic patients

To investigate cortical bone composition and the role of the insulin-like g rowth factor (IGF) system in active acromegaly, iliac crest bone biopsies w ere obtained from 15 patients (3 women and 12 men), aged 21-64 yr (mean, 45 .6 yr), and 25 age- and sex-matched controls (8 women and 17 men), aged 22- 66 yr (mean, 44.6 yr). Levels of IGF-I, IGF-II, IGF-binding protein-3 (IGFB P-3), IGFBP-5, and total protein were determined in extracts obtained after ethylenediamine tetraacetate and guanidine hydrochloride extraction. Osteo calcin and calcium were determined in extracts after HCl hydrolysis. Cortic al bone contents of IGF-I, EGF-II, and IGFBP-5 were significantly elevated in the acromegalic patients compared with control values [91% (P < 0.001), 44% (P < 0.04), and 115% (P < 0.004), respectively]. There was no significa nt difference in IGFBP-3, osteocalcin, protein, and calcium between patient s and controls. This study suggests that the increased levels of growth fac tors in cortical bone from acromegalics is a reflection of local production , secondary to a chronic systemic excess of GH and IGF-I.