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Vitamin A improves insulin sensitivity by increasing insulin receptor phosphorylation through protein tyrosine phosphatase 1B regulation at early age in obese rats of WNIN/Ob strain
Author(s) -
Jeyakumar S. M.,
Vijaya Kumar P.,
Giridharan N. V.,
Vajreswari A.
Publication year - 2011
Publication title -
diabetes, obesity and metabolism
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.445
H-Index - 128
eISSN - 1463-1326
pISSN - 1462-8902
DOI - 10.1111/j.1463-1326.2011.01407.x
Subject(s) - medicine , endocrinology , insulin resistance , insulin , insulin receptor , vitamin , obesity , leptin , biology
To test the hypothesis that early intervention of vitamin A‐enriched diet contains the development of obesity and improves insulin resistance, 50‐day‐old male lean and obese rats of WNIN/Ob strain were given either stock diet (2.6 mg vitamin A/kg diet) or vitamin A‐enriched diet (129 mg vitamin A/kg diet) for 3 months. Compared with stock diet‐fed obese rats, vitamin A‐enriched diet‐fed obese rats had reduced body weight gain, visceral adiposity and improved insulin sensitivity as evidenced by decreased fasting plasma insulin and unaltered glucose levels, which could possibly be due to higher phosphorylation of soleus muscle insulin receptor. This in turn is explained by decreased protein tyrosine phosphatase 1B (PTP1B) levels. Most of these changes were not observed in lean rats. In conclusion, chronic feeding of vitamin A‐enriched diet to obese rats at an early age ameliorates visceral adiposity and improves the insulin sensitivity, possibly by decreasing soleus muscle PTP1B levels.