Exaggerated response to mild stress in rats fed high-fat diet

Ariadne Legendre, Ruth Babette Harris

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

It has been suggested that high-fat (HF) diet exaggerates the stress-induced release of glucocorticoids due to activation of the hypothalamic-pituitary-adrenal (HPA) axis. In an initial experiment, in which rats were fed HF diet for 4 days, we found that HF-fed controls stopped gaining weight, indicating that they were hyperresponsive to the mild stress of tail bleeding but responded the same as low-fat (LF)-fed rats to the more severe stress of restraint. A second experiment confirmed these results when rats fed a HF diet for 4 days showed an exaggerated corticosterone release in response to an intraperitoneal injection of saline and movement to a novel cage, compared with LF-fed rats. Experiment 3 tested the same parameters as experiment 2 but interchanged the diets. This allowed us to differentiate between the effects of the dietary fat and the novelty of the diet. Additionally, this experiment determined whether hyperresponsiveness to mild stress in HF-fed rats was sustained during a prolonged exposure to diet. The results confirmed that a HF diet, not novelty, exaggerated the endocrine stress response after 9 days on the diet but that the effect was no longer present after 23 days on the diet. The hyperresponsiveness of the HPA axis in HF-fed rats is similar to that observed in animals that have been exposed to a significant chronic or acute stress, suggesting that the HF diet may initially be perceived as a stressor.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume291
Issue number5
DOIs
StatePublished - Nov 24 2006
Externally publishedYes

Fingerprint

High Fat Diet
Fats
Diet
Dietary Fats
Corticosterone
Intraperitoneal Injections
Glucocorticoids
Tail
Hemorrhage
Weights and Measures

Keywords

  • Corticotropin-relasing factor
  • Energy intake
  • Hypothalamo-pituitary axis
  • Weight regulation

ASJC Scopus subject areas

  • Physiology

Cite this

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abstract = "It has been suggested that high-fat (HF) diet exaggerates the stress-induced release of glucocorticoids due to activation of the hypothalamic-pituitary-adrenal (HPA) axis. In an initial experiment, in which rats were fed HF diet for 4 days, we found that HF-fed controls stopped gaining weight, indicating that they were hyperresponsive to the mild stress of tail bleeding but responded the same as low-fat (LF)-fed rats to the more severe stress of restraint. A second experiment confirmed these results when rats fed a HF diet for 4 days showed an exaggerated corticosterone release in response to an intraperitoneal injection of saline and movement to a novel cage, compared with LF-fed rats. Experiment 3 tested the same parameters as experiment 2 but interchanged the diets. This allowed us to differentiate between the effects of the dietary fat and the novelty of the diet. Additionally, this experiment determined whether hyperresponsiveness to mild stress in HF-fed rats was sustained during a prolonged exposure to diet. The results confirmed that a HF diet, not novelty, exaggerated the endocrine stress response after 9 days on the diet but that the effect was no longer present after 23 days on the diet. The hyperresponsiveness of the HPA axis in HF-fed rats is similar to that observed in animals that have been exposed to a significant chronic or acute stress, suggesting that the HF diet may initially be perceived as a stressor.",
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AB - It has been suggested that high-fat (HF) diet exaggerates the stress-induced release of glucocorticoids due to activation of the hypothalamic-pituitary-adrenal (HPA) axis. In an initial experiment, in which rats were fed HF diet for 4 days, we found that HF-fed controls stopped gaining weight, indicating that they were hyperresponsive to the mild stress of tail bleeding but responded the same as low-fat (LF)-fed rats to the more severe stress of restraint. A second experiment confirmed these results when rats fed a HF diet for 4 days showed an exaggerated corticosterone release in response to an intraperitoneal injection of saline and movement to a novel cage, compared with LF-fed rats. Experiment 3 tested the same parameters as experiment 2 but interchanged the diets. This allowed us to differentiate between the effects of the dietary fat and the novelty of the diet. Additionally, this experiment determined whether hyperresponsiveness to mild stress in HF-fed rats was sustained during a prolonged exposure to diet. The results confirmed that a HF diet, not novelty, exaggerated the endocrine stress response after 9 days on the diet but that the effect was no longer present after 23 days on the diet. The hyperresponsiveness of the HPA axis in HF-fed rats is similar to that observed in animals that have been exposed to a significant chronic or acute stress, suggesting that the HF diet may initially be perceived as a stressor.

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