title: Omentin-1 levels are reduced by pharmacologic doses of leptin, but remain unaffected by energy deprivation and display no day-night variation.
abstract: OBJECTIVE
  To study the day-night variation of omentin-1 levels and assess whether leptin and/or short- and long-term energy deprivation alter circulating omentin-1 levels via cytokines.
  
  
  METHODS
  Omentin-1 levels were measured hourly in serum samples from six healthy men to evaluate for day-night variation. To study effects of acute energy deprivation and of leptin administration, eight healthy subjects were studied in the fasting state for 72 h with administration of either placebo or metreleptin (recombinant human leptin) in physiologic replacement doses. We evaluated the effect of leptin in pharmacologic doses on serum omentin-1 and cytokine levels, as well as on omentin-1 levels in ex vivo omental adipose tissue, in 15 healthy volunteers. To study the effect of chronic energy deprivation and weight loss on omentin-1 levels, we followed 18 obese subjects for 12 months who underwent bariatric surgery.
  
  
  RESULTS
  There is no day-night variation in omentin-1 levels. Short-term and chronic energy deprivation, as well as ex vivo leptin administration and physiologic replacement doses of leptin, do not alter omentin-1 levels; pharmacologic doses of metreleptin reduce omentin-1 levels, whereas levels of tumor necrosis factor-α receptor II and interleukin-6 tend to increase.
  
  
  CONCLUSIONS
  Omentin-1 levels are reduced by pharmacologic doses of metreleptin independent of effects on cytokine levels.
authors.affiliation: Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.|Section of Endocrinology, Veteran's Affairs Boston Healthcare System, Harvard Medical School, Boston, MA.
authors.forename: Ole-Petter Riksfjord
authors.initials: OR
authors.lastname: Hamnvik
authors.affiliation: Section of Endocrinology, Veteran's Affairs Boston Healthcare System, Harvard Medical School, Boston, MA.|Section of Endocrinology, Diabetes and Nutrition, Boston Medical Center, Boston University School of Medicine, Boston, MA.|Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Bindiya
authors.initials: B
authors.lastname: Thakkar
authors.affiliation: Section of Endocrinology, Veteran's Affairs Boston Healthcare System, Harvard Medical School, Boston, MA.|Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: John
authors.initials: J
authors.lastname: Chamberland
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Aronis
authors.affiliation: Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Schneider
authors.affiliation: Section of Endocrinology, Veteran's Affairs Boston Healthcare System, Harvard Medical School, Boston, MA.|Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Christos S
authors.initials: CS
authors.lastname: Mantzoros
mesh_terms: D050110:Bariatric Surgery; D002940:Circadian Rhythm; D016207:Cytokines / Q000097:blood* / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004734:Energy Metabolism / Q000187:drug effects*; D005215:Fasting; D058851:GPI-Linked Proteins / Q000097:blood / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D037102:Lectins / Q000097:blood* / Q000187:drug effects / Q000378:metabolism; D020738:Leptin / Q000031:analogs & derivatives* / Q000494:pharmacology; D009765:Obesity / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects; D015431:Weight Loss
chemical_list: D016207:Cytokines; D058851:GPI-Linked Proteins; C432397:ITLN1 protein, human; D015850:Interleukin-6; D037102:Lectins; D020738:Leptin; D014409:Tumor Necrosis Factor-alpha; C415771:metreleptin