@article{HankirPattPattetal.2017,
  author    = {Hankir, Mohammed K. and Patt, Marianne and Patt, J{\"o}rg T. W. and Becker, Georg A. and Rullmann, Michael and Kranz, Mathias and Deuther-Conrad, Winnie and Schischke, Kristin and Seyfried, Florian and Brust, Peter and Hesse, Swen and Sabri, Osama and Kr{\"u}gel, Ute and Fenske, Wiebke},
  title     = {Suppressed fat appetite after Roux-en-Y gastric bypass surgery associates with reduced brain mu-opioid receptor availability in diet-induced obese male rats},
  series = {Frontiers in Neuroscience},
  volume    = {10},
  journal   = {Frontiers in Neuroscience},
  doi       = {10.3389/fnins.2016.00620},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181130},
  year      = {2017},
  abstract  = {Brain μ-opioid receptors (MORs) stimulate high-fat (HF) feeding and have been implicated in the distinct long term outcomes on body weight of bariatric surgery and dieting. Whether alterations in fat appetite specifically following these disparate weight loss interventions relate to changes in brain MOR signaling is unknown. To address this issue, diet-induced obese male rats underwent either Roux-en-Y gastric bypass (RYGB) or sham surgeries. Postoperatively, animals were placed on a two-choice diet consisting of low-fat (LF) and HF food and sham-operated rats were further split into ad libitum fed (Sham-LF/HF) and body weight-matched (Sham-BWM) to RYGB groups. An additional set of sham-operated rats always only on a LF diet (Sham-LF) served as lean controls, making four experimental groups in total. Corresponding to a stage of weight loss maintenance for RYGB rats, two-bottle fat preference tests in conjunction with small-animal positron emission tomography (PET) imaging studies with the selective MOR radioligand [\(^{11}\)C]carfentanil were performed. Brains were subsequently collected and MOR protein levels in the hypothalamus, striatum, prefrontal cortex and orbitofrontal cortex were analyzed by Western Blot. We found that only the RYGB group presented with intervention-specific changes: having markedly suppressed intake and preference for high concentration fat emulsions, a widespread reduction in [\(^{11}\)C]carfentanil binding potential (reflecting MOR availability) in various brain regions, and a downregulation of striatal and prefrontal MOR protein levels compared to the remaining groups. These findings suggest that the suppressed fat appetite caused by RYGB surgery is due to reduced brain MOR signaling, which may contribute to sustained weight loss unlike the case for dieting.},
  language  = {en}
}
@article{RefardtSailerWinzeleretal.2018,
  author    = {Refardt, Julie and Sailer, Clara Odilia and Winzeler, Bettina and Betz, Matthias Johannes and Chifu, Irina and Schnyder, Ingeborg and Fassnacht, Martin and Fenske, Wiebke and Christ-Crain, Mirjam},
  title     = {FGF-21 levels in polyuria-polydipsia syndrome},
  series = {Endocrine Connections},
  volume    = {7},
  journal   = {Endocrine Connections},
  number    = {12},
  doi       = {10.1530/EC-18-0469},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225085},
  pages     = {1501-1506},
  year      = {2018},
  abstract  = {The pathomechanism of primary polydipsia is poorly understood. Recent animal data reported a connection between fibroblast growth factor 21 (FGF-21) and elevated fluid intake independently of hormonal control by the hormone arginine-vasopressin (AVP) and osmotic stimulation. We therefore compared circulating FGF-21 levels in patients with primary polydipsia to patients with AVP deficiency (central diabetes insipidus) and healthy volunteers. In this prospective cohort study, we analyzed FGF-21 levels of 20 patients with primary polydipsia, 20 patients with central diabetes insipidus and 20 healthy volunteers before and after stimulation with hypertonic saline infusion targeting a plasma sodium level >= 150 mmol/L. The primary outcome was the difference in FGF-21 levels between the three groups. Baseline characteristics were similar between the groups except for patients with central diabetes insipidus being heavier. There was no difference in baseline FGF-21 levels between patients with primary polydipsia and healthy volunteers (122 pg/mL (52,277) vs 193 pg/mL (48,301), but higher levels in patients with central diabetes insipidus were observed (306 pg/mL (114,484); P=0.037). However, this was not confirmed in a multivariate linear regression analysis after adjusting for age, sex, BMI and smoking status. Osmotic stimulation did not affect FGF-21 levels in either group (difference to baseline: primary polydipsia -23 pg/mL (-43, 22); central diabetes insipidus 17 pg/mL (-76, 88); healthy volunteers -6 pg/mL (-68, 22); P=0.45). To conclude, FGF-21 levels are not increased in patients with primary polydipsia as compared to central diabetes insipidus or healthy volunteers. FGF-21 therefore does not seem to be causal of elevated fluid intake in these patients.},
  subject      = {Fibroblast Growth Factor-21},
  language  = {en}
}