title: A paradox: insulin inhibits expression and secretion of resistin which induces insulin resistance.
abstract: OBJECTIVE
  To confirm whether insulin regulates resistin expression and secretion during differentiation of 3T3-L1 preadipocytes and the relationship of resistin with insulin resistance both in vivo and in vitro.
  
  
  METHODS
  Supernatant resistin was measured during differentiation of 3T3-L1 preadipocytes. L6 rat myoblasts and hepatoma cell line H4IIE were used to confirm the cellular function of resistin. Diet-induced obese rats were used as an insulin resistance model to study the relationship of resistin with insulin resistance.
  
  
  RESULTS
  Resistin expression and secretion were enhanced during differentiation 3T3-L1 preadipocytes. This cellular differentiation stimulated resistin expression and secretion, but was suppressed by insulin. Resistin also induced insulin resistance in H4IIE hepatocytes and L6 myoblasts. In diet-induced obese rats, serum resistin levels were negatively correlated with insulin sensitivity, but not with serum insulin.
  
  
  CONCLUSIONS
  Insulin can inhibit resistin expression and secretion in vitro, but insulin is not a major regulator of resistin in vivo. Fat tissue mass affects insulin sensitivity by altering the expression and secretion of resistin.
authors.affiliation: Institute of Pediatrics of Nanjing Maternity and Child Health Hospital of the Nanjing Medical University, Nanjing 210004, Jiangsu Province, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.forename: Hong-Qi
authors.initials: HQ
authors.lastname: Fan
authors.forename: Jie
authors.initials: J
authors.lastname: Qiu
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Nan
authors.initials: N
authors.lastname: Gu
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Fei
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Pan
authors.forename: Mei
authors.initials: M
authors.lastname: Guo
authors.forename: Rong-Hua
authors.initials: RH
authors.lastname: Chen
authors.forename: Xi-Rong
authors.initials: XR
authors.lastname: Guo
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D051379:Mice; D009765:Obesity / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D052243:Resistin / Q000235:genetics / Q000378:metabolism*
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin; D012333:RNA, Messenger; D052243:Resistin