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Objective: Obesity and liver fat are associated with decreased levels of serum sex hormone binding globulin (SHBG). Laboratory studies suggest that hepatic de novo lipogenesis (DNL) is involved in the downregulation of SHBG synthesis. The aim of the present study was to address the role of DNL on serum SHBG in humans., Design: A cross-sectional study examining the association between DNL, measured by stable isotopes, and serum SHBG, stratified by sex., Participants: Healthy men (n = 34) and women (n = 21) were combined from two cross-sectional studies. Forty-two per cent of participants had hepatic steatosis, and the majority were overweight (62%) or obese (27%)., Results: DNL was inversely associated with SHBG in women (β: -0.015, 95% CI: -0.030; 0.000), but not in men (β: 0.007, 95% CI: -0.005; 0.019) (p for interaction = .068). Adjustment for study population, age and body mass index did not materially change these results, although statistical significance was lost after adjustment for serum insulin., Conclusions: An inverse association between DNL and SHBG may explain the decreased SHBG levels that are observed in obesity, at least in women., (© 2021 The Authors. Clinical Endocrinology published by John Wiley & Sons Ltd.)

Objective: Increasing overnight fasting time seems a promising strategy to improve metabolic health in individuals with nonalcoholic fatty liver (NAFL). Mechanisms underlying the beneficial effects of fasting may be related to larger fluctuations in hepatic glycogen and higher fat oxidation. This study investigated whether prolonging an overnight fast depletes hepatic glycogen stores and improves substrate metabolism in individuals with NAFL and healthy lean individuals. Methods: Eleven individuals with NAFL and ten control individuals participated in this randomized crossover trial. After a 9.5‐hour or 16‐hour fast, hepatic glycogen was measured by using carbon‐13 magnetic resonance spectroscopy, and a meal test was performed. Nocturnal substrate oxidation was measured with indirect calorimetry. Results: Extending fasting time led to lower nocturnal carbohydrate oxidation and higher fat oxidation in both groups (intervention × time, p < 0.005 for carbohydrate and fat oxidation). In both arms, the respiratory exchange ratio measured during the night remained higher in the group with NAFL compared with the control group (population p < 0.001). No changes were observed in hepatic glycogen depletion with a prolonged overnight fast in the group with NAFL or the control group. Conclusions: These results suggest that acutely prolonging the overnight fast can improve overnight substrate oxidation and that these alterations are not mediated by changes in hepatic glycogen depletion. [ABSTRACT FROM AUTHOR]