Reduced plasma concentrations of transforming growth factor β1 (TGF-β1) in obese women

OBJECTIVE: To evaluate Transforming Growth Factor β1 (TGF-β1) plasma concentrations and the possible relationship between this growth factor and various hormones in obese women. DESIGN: Case-control study. SETTING: Outpatient’s Service for the Prevention and Treatment of Obesity at the University Hospital. SUBJECTS: Twenty-five women with mild to moderate obesity, and 15 non-obese healthy women were used as controls. MEASUREMENTS: Evaluation of TGF-β1, insulin, prolactin, sex-hormone binding globulin, androstenedione, free triiodothyronine, free tetraiodothyronine, thyroid-stimulating hormone, dehydroepiandrosterone-sulfate, testosterone, insulin-like growth factor 1, cortisol and adrenocorticotropic hormone plasma concentrations in obese women. Blood samples were taken from fasting subjects for the determination of the above parameters. RESULTS: In obese women plasma TGF-β1 concentrations were lower than in controls. The obese subjects also had lower GH, IGF-1 and SHBG plasma concentrations and increased insulinaemia. A positive correlation was found between TGF-β1 and both IGF-1 (r=0.52; P<0.01) and DHEA-S (r=0.43; P<0.05), while a negative correlation was found between TGF-β1 and SHBG (r=−0.49; P<0.05). CONCLUSIONS: The reduction in TGF-β1, an antilipogenic factor, may play a role in the pathogenesis of obesity and could be involved in the development of some obesity-related endocrine alterations.