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Effects of Obesity on Serum Insulin‐Like Growth Factor 1 (IGF‐1) Levels Using DMBA‐Induced Ovariectomized Zucker Rat Model.
Author(s) -
Hakkak Reza,
Shaaf Saeid,
Macleod Stewart,
Cockrell Gail,
Korourian Soheila
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.886.7
Subject(s) - ovariectomized rat , dmba , medicine , endocrinology , obesity , mammary tumor , breast cancer , estrogen , cancer , carcinogenesis
Obesity is associated with increased risk for post‐menopausal women. Several studies have suggested that IGF‐1 plays an important role in promotion and progression of breast cancer. The main objective of this study was to use DMBA‐induced ovariectomized obese zucker rat model to investigate the effects of obesity on serum IGF‐1 levels. Lean and obese rats were sham operated or ovariectomized at age 40 days and were gavaged at age 50 days with 65 mg/kg DMBA. Rats were killed 135 days post‐DMBA treatment. Serum IGF1 was measured by ELISA. Thirty‐six (36%) of the obese ovariectomized rats (O/O) developed mammary tumors while lean ovariectomized (L/O) rats developed no mammary tumors ( P <0.001). The obese sham (O/S) rats developed mammary tumors (59%) compared to 30% of the lean sham (L/S) rats ( P <0.05). Ovariectomy caused a significant ( P <0.001) increase in serum IGF‐1 for ovariectomized lean group but not in obese group. Also, obesity significantly increased (P<0.001) serum IGF‐1 in both sham and ovariectomized rats compared to lean rats. Our results suggest that obesity is a major risk for DMBA‐induced mammary tumor development and elevated IGF‐1 levels may be associated with the increased susceptibility to DMBA‐induced mammary tumors. Other mechanisms responsible for increased mammary tumor susceptibility in obese rats are under investigation. (Supported by Susan G. Komen Foundation and ABI to RH).