Androgens May Mediate a Relative Preservation of IGF-I Levels in Overweight and Obese Women Despite Reduced Growth Hormone Secretion
| Autor: | Patrick M. Sluss, Andrea L. Utz, Jeffrey Breu, Karen K. Miller, A. Yamamoto |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Adult
medicine.medical_specialty Endocrinology Diabetes and Metabolism Clinical Biochemistry Context (language use) Estrone Overweight Biochemistry Body Mass Index chemistry.chemical_compound Endocrinology Sex hormone-binding globulin Sex Hormone-Binding Globulin Internal medicine medicine Humans Obesity Insulin-Like Growth Factor I Gonadal Steroid Hormones Testosterone biology Human Growth Hormone business.industry Biochemistry (medical) medicine.disease Growth hormone secretion Circadian Rhythm Cross-Sectional Studies chemistry Androgens biology.protein Original Article Female medicine.symptom business Body mass index |
| Zdroj: | The Journal of Clinical Endocrinology & Metabolism. 93:4033-4040 |
| ISSN: | 1945-7197 0021-972X |
| Popis: | Obesity is characterized by reduced GH secretion, but data regarding IGF-I levels and their determinants are conflicting.The objectives were to determine whether IGF-I levels are reduced and to investigate determinants of GH and IGF-I in healthy overweight and obese women.A cross-sectional study was performed.The study was conducted at a General Clinical Research Center.Thirty-four healthy women without pituitary/hypothalamic disease participated, including 11 lean [body mass index (BMI)25 kg/m(2)], 12 overweight (BMIor =25 kg/m(2) and30 kg/m(2)), and 11 obese (BMIor =30 kg/m(2)) women of comparable age (overall mean age, 30.7 +/- 7.8 yr).There was no intervention.The main outcome measures were frequent sampling (every 10 min for 24 h) for GH, peak GH after GHRH-arginine stimulation, IGF-I, IGF binding protein-3, estrone, estradiol, testosterone, free testosterone, SHBG, homeostasis model assessment of insulin resistance, and abdominal fat.Mean 24-h GH and peak stimulated GH were lower in overweight than lean women and lowest in obese women. Mean IGF-I levels trended lower in obese, but not overweight, compared with lean women. Free testosterone was positively associated with IGF-I (R = 0.36, P = 0.04) but not with GH measures. Visceral fat was the only determinant of mean 24-h GH (R(2) = 0.66, P0.0001) and of peak stimulated GH (R(2) = 0.63, P0.0001), and mean 24-h GH accounted for 39% of the variability of IGF-I (P = 0.0002), with an additional 28% (P0.0001) attributable to free testosterone levels.Despite a linear decrease in GH secretion and peak stimulated GH levels with increasing BMI in healthy overweight and obese women, IGF-I levels were not commensurately reduced. Androgens may contribute to this relative preservation of IGF-I secretion in overweight and obese women despite reduced GH secretion. |
| Databáze: | OpenAIRE |
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