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High‐fat diet induced insulin resistance is more robust and reliable in Wistar than Spraque‐Dawley rats
Author(s) -
Jun Lucy Soo Yon,
Fehn Richard
Publication year - 2006
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.20.4.a447-d
Subject(s) - medicine , endocrinology , insulin resistance , obesity , insulin , chemistry , diabetes mellitus , respiratory system
A comparison of the growth patterns, metabolic substrate preferences, and insulin responsiveness revealed that Wistar (W) rats provide a more robust and reliable model for diet‐induced obesity (DIO) and diabetes mellitus than the widely‐used Spraque‐Dawley (SD) model. Male SD and W rats 25–28 days of age (n=28–32) were fed high‐fat (HF) rodent chow (45% kcal from fat derived from vegetable oil) for 7 months and 11 weeks, respectively, to induce obesity and insulin resistance. HF fed W rats achieved greater body weights by 78–97 days of age than did SD rats by age 145–159 days (501.3±9.2 v 482.9±7.4 g, respectively; P<0.001). Oral Glucose Tolerance Tests (OGTT, 40 mg/kg BW) performed on SD rats showed variable responsiveness following 16, 22 and 48 h of fasting. Metabolic depression in the 48h fasted animals was associated with a lower peak blood glucose concentration (125 mg%) at 30 min. but persistent hyperglycemia at 120 min. Similar peak glucose concentrations were observed at 30 min. in 16h (135 mg%) and 22h fasted animals (141 mg%) with both achieving baseline values by 120 min., although the 22h fasted animals were significantly lower (96 mg% v 118 mg%) by 60 min. In comparison to 16h fasted SD rats, the W rats sustained higher serum glucose concentrations at 60, 90, and 120 min (11%, 14%, and 17% greater than SD, respectively; P<0.05) without returning to baseline. Respiratory gas analysis revealed that the HF SD rats utilize considerably more lipid as a metabolic substrate in comparison to HF W rats (RQ 0.78 v 1.0, respectively, P<0.05) which may explain the enhanced impact of HF diet on the latter. W rats exhibited accelerated weight gains and longer recovery times for OGTT indicating greater susceptibility to HF‐induced obesity and insulin resistance. Funded by CSUSB Faculty Development Program (RF) and ASI (LJ). HF diet generously provided by Research Diets, Inc.