INTRODUCTION: The GH-IGF axis has profound effects on bone metabolism and may be important in the etiology of idiopathic osteoporosis. Serum IGF-I is often low in men with osteoporosis, which may be attributable to GH hypo-secretion or hepatic GH insensitivity. We studied the GH-IGF axis in depth to look for evidence to support these hypotheses. MATERIALS AND METHODS: 28 healthy 60- to 70-year-old men with low, intermediate, or normal BMD were studied. GH secretion was measured by overnight urine collection. GH reserve was assessed by exercise and glucagon stimulation tests. Hepatic IGF-I production was investigated using a GH-IGF-I generation test. Data were analyzed using Pearson's correlation coefficient, linear regression, and analysis of variance. RESULTS: Serum IGF-I was reduced in subjects with low BMD (P = 0.009). There was no difference in GH secretion or reserve between the groups. Overall, GH reserve and IGF-I were positively related but this was attenuated in the low BMD group. However, no statistically significant difference in IGF-I generation capacity between BMD groups was found. CONCLUSIONS: Men with reduced BMD have low IGF-I but normal GH secretion and reserve. Our data suggested, but could not confirm, hepatic resistance to GH as a mechanism for this association.
INTRODUCTION: The GH-IGF axis has profound effects on bone metabolism and may be important in the etiology of idiopathic osteoporosis. Serum IGF-I is often low in men with osteoporosis, which may be attributable to GH hypo-secretion or hepatic GH insensitivity. We studied the GH-IGF axis in depth to look for evidence to support these hypotheses. MATERIALS AND METHODS: 28 healthy 60- to 70-year-old men with low, intermediate, or normal BMD were studied. GH secretion was measured by overnight urine collection. GH reserve was assessed by exercise and glucagon stimulation tests. Hepatic IGF-I production was investigated using a GH-IGF-I generation test. Data were analyzed using Pearson's correlation coefficient, linear regression, and analysis of variance. RESULTS: Serum IGF-I was reduced in subjects with low BMD (P = 0.009). There was no difference in GH secretion or reserve between the groups. Overall, GH reserve and IGF-I were positively related but this was attenuated in the low BMD group. However, no statistically significant difference in IGF-I generation capacity between BMD groups was found. CONCLUSIONS:Men with reduced BMD have low IGF-I but normal GH secretion and reserve. Our data suggested, but could not confirm, hepatic resistance to GH as a mechanism for this association.
Authors: Manthos G Giannoulis; Finbarr C Martin; K Sreekumaran Nair; A Margot Umpleby; Peter Sonksen Journal: Endocr Rev Date: 2012-03-20 Impact factor: 19.871
Authors: L Esterle; J-P Sabatier; F Guillon-Metz; O Walrant-Debray; G Guaydier-Souquières; F Jehan; M Garabédian Journal: Osteoporos Int Date: 2008-08-14 Impact factor: 4.507
Authors: Francisco J A de Paula; Miburge B Góis-Júnior; Manuel H Aguiar-Oliveira; Francisco de A Pereira; Carla R P Oliveira; Rossana M C Pereira; Catarine T Farias; Tábita A R Vicente; Roberto Salvatori Journal: Clin Endocrinol (Oxf) Date: 2008-05-20 Impact factor: 3.478