Phenotypic sexual dimorphism in response to dietary fat manipulation in C57BL/6J mice.
Study Goal
The researchers aimed to determine the sex-specific metabolic responses to different dietary fat compositions (low-fat, Western, and high-fat diets) in C57BL/6 J mice.
Results Summary
Male and female mice exhibited different metabolic responses to high-fat diets, with males showing earlier weight gain, reduced locomotor activity, impaired glucose tolerance, and increased pancreatic β cell area, while females displayed increased energy expenditure and less severe metabolic disruptions.
Population
Male and female C57BL/6 J mice starting at 4 weeks of age.
Effective Dosage
Low-fat diet (10% calories from fat), Western Diet (45% calories from fat), high-fat diet (60% calories from fat).
Duration
20 weeks.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Western Diet (WD, 45% calories from fat) | increase | total percent body weight gain | male and female C57BL/6 J mice | - | similar increases in total percent body weight gain | #1 |
high fat diet (HFD, 60% calories from fat) | increase | total percent body weight gain | male and female C57BL/6 J mice | - | similar increases in total percent body weight gain | #2 |
high fat diet (HFD, 60% calories from fat) | increase | weight gain | male mice | - | gained weight earlier | #3 |
Western Diet (WD, 45% calories from fat) | increase | weight gain | male mice | - | gained weight earlier | #4 |
Western Diet (WD, 45% calories from fat) | no change | caloric food intake | male mice | - | maintained their caloric food intake | #5 |
high fat diet (HFD, 60% calories from fat) | no change | caloric food intake | male mice | - | maintained their caloric food intake | #6 |
Western Diet (WD, 45% calories from fat) | decrease | locomotor activity | male mice | - | reducing their locomotor activity | #7 |
high fat diet (HFD, 60% calories from fat) | decrease | locomotor activity | male mice | - | reducing their locomotor activity | #8 |
Western Diet (WD, 45% calories from fat) | increase | caloric food intake | female mice | - | increased their caloric food intake | #9 |
Western Diet (WD, 45% calories from fat) | no change | locomotor activity | female mice | - | did not significantly change | #10 |
high fat diet (HFD, 60% calories from fat) | no change | locomotor activity | female mice | - | did not significantly change | #11 |
Western Diet (WD, 45% calories from fat) | increase | energy expenditure | female mice | - | exhibited increased energy expenditure | #12 |
high fat diet (HFD, 60% calories from fat) | increase | energy expenditure | female mice | - | exhibited increased energy expenditure | #13 |
dietary intervention | decrease | glucose tolerance | male mice | - | impaired glucose tolerance that was worse | #14 |
high fat diet (HFD, 60% calories from fat) | increase | pancreatic β cell area | male mice | - | exhibited an increase in pancreatic β cell area | #15 |
high fat diet (HFD, 60% calories from fat) | decrease | insulin sensitivity | male mice | - | reduced insulin sensitivity | #16 |
BACKGROUND: Obesity and the metabolic syndrome are increasingly prevalent in society and their complications and response to treatment exhibit sexual dimorphism. Mouse models of high fat diet-induced obesity are commonly used for both mechanistic and therapeutic studies of metabolic disease and diabetes. However, the inclusion of female mammals in obesity research has not been a common practice, and has resulted in a paucity of data regarding the effect of sex on metabolic parameters and its applicability to humans. METHODS: Here we analyzed male and female C57BL/6 J mice beginning at 4 weeks of age that were placed on a low-fat diet (LFD, 10% calories from fat), a Western Diet (WD, 45% calories from fat), or a high fat diet (HFD, 60% calories from fat). Assessments of body composition, glucose homeostasis, insulin production, and energy metabolism, as well as histological analyses of pancreata were performed. RESULTS: Both male and female C57BL/6 J mice had similar increases in total percent body weight gain with both WD and HFD compared to LFD, however, male mice gained weight earlier upon HFD or WD feeding compared to female mice. Male mice maintained their caloric food intake while reducing their locomotor activity with either WD or HFD compared to LFD, whereas female mice increased their caloric food intake with WD feeding. Locomotor activity of female mice did not significantly change upon WD or HFD feeding, yet female mice exhibited increased energy expenditure compared to WD or HFD fed male mice. Glucose tolerance tests performed at 4, 12 and 20 weeks of dietary intervention revealed impaired glucose tolerance that was worse in male mice compared to females. Furthermore, male mice exhibited an increase in pancreatic β cell area as well as reduced insulin sensitivity after HFD feeding compared to WD or LFD, whereas female mice did not. CONCLUSIONS: Male and female C57BL/6 J mice exhibited strikingly different responses in weight, food consumption, locomotor activity, energy expenditure and β cell adaptation upon dietary manipulation, with the latter exhibiting less striking phenotypic changes. We conclude that the nature of these responses emphasizes the need to contextualize studies of obesity pathophysiology and treatment with respect to sex.