Effects of GH and/or sex steroids on circulating IGF-I and IGFBPs in healthy, aged women and men
| Autor: | Thomas Münzer, S. Mitchell Harman, John D. Sorkin, Clifford J. Rosen, Katherine M. Pabst, Marc R. Blackman, Carol St. Clair |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Blood Glucose
Male medicine.medical_specialty Physiology Endocrinology Diabetes and Metabolism medicine.medical_treatment Osteocalcin Medroxyprogesterone Acetate Growth hormone Insulin-like growth factor-binding protein Double-Blind Method Physiology (medical) Internal medicine medicine Humans Insulin Testosterone Insulin-Like Growth Factor I Gonadal Steroid Hormones Aged Aged 80 and over Estradiol biology Human Growth Hormone business.industry Body Weight Insulin-Like Growth Factor Binding Protein 1 Insulin-Like Growth Factor Binding Proteins Insulin-Like Growth Factor Binding Protein 2 Insulin-Like Growth Factor Binding Protein 3 Endocrinology Insulin-Like Growth Factor Binding Protein 4 Sex steroid biology.protein Female Insulin-Like Growth Factor Binding Protein 5 business hormones hormone substitutes and hormone antagonists Hormone |
| Zdroj: | American Journal of Physiology-Endocrinology and Metabolism. 290:E1006-E1013 |
| ISSN: | 1522-1555 0193-1849 |
| DOI: | 10.1152/ajpendo.00166.2005 |
| Popis: | Circulating GH, IGF-I, IGFBP-3, and sex steroid concentrations decrease with age. GH or sex steroid treatment increases IGFBP-3, but little is known regarding the effects of these hormones on other IGFBPs. We assessed the effects of 26 wk of administration of GH, sex steroids, or GH + sex steroids on AM levels of IGF-I, IGFBPs 1–5, insulin, glucose, and osteocalcin and 2-h urinary excretion of deoxypyridinolline (DPD) cross-links in 53 women and 71 men aged 65–88 yr. Before treatment, in women and men, IGF-I was directly related to IGFBP-3 ( P < 0.001 and P < 0.0001) and IGFBP-1 to IGFBP-2 ( P = 0.0001). In women, IGFBP-1 was inversely related to insulin ( P < 0.0005) and glucose ( P < 0.005) and IGFBP-4 to osteocalcin ( P < 0.01). IGFBP-4 and IGFBP-5 were not significantly related to DPD cross-links. GH and/or sex steroid increased IGF-I levels in both sexes, with higher concentrations in men ( P < 0.001). In women, the IGF-I increment after GH was attenuated by hormone replacement therapy (HRT) coadministration ( P < 0.05). Hormone administration also increased IGFBP-3. IGFBP-1 was unaffected by GH + sex steroids, whereas GH decreased IGFBP-2 by 15% in men ( P < 0.05). Hormone administration did not change IGFBP-4, whereas in men IGFBP-5 increased by 20% after GH ( P < 0.05) and 56% after GH + testosterone ( P = 0.0003). These data demonstrate sexually dimorphic IGFBP responses to GH. Additonally, HRT attenuated or prevented GH-mediated increases in IGF-I and IGFBP-3. Whether GH and/or sex steroid administration alters local tissue production of IGFBPs and whether the latter influence autocrine or paracrine actions of IGF-I remain to be determined. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|