A paradox: insulin inhibits expression and secretion of resistin which induces insulin resistance.
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.
Liu
Feng
F
Institute of Pediatrics of Nanjing Maternity and Child Health Hospital of the Nanjing Medical University, Nanjing 210004, Jiangsu Province, China.
Fan
Hong-Qi
HQ
Qiu
Jie
J
Wang
Bin
B
Zhang
Min
M
Gu
Nan
N
Zhang
Chun-Mei
CM
Fei
Li
L
Pan
Xiao-Qing
XQ
Guo
Mei
M
Chen
Rong-Hua
RH
Guo
Xi-Rong
XR
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*
D007004:Hypoglycemic Agents; D007328:Insulin; D012333:RNA, Messenger; D052243:Resistin