Corticosterone administration in drinking water decreases high-fat diet intake but not preference in male rats

Abstract

One of the mechanisms through which regular exercise contributes to weight maintenance could be by reducing intake and preference for high-fat (HF) diets. Indeed, we previously demonstrated that wheel-running rats robustly reduced HF diet intake and preference. The reduced HF diet preference by wheel running can be so profound that the rats consumed only the chow diet and completely avoided the HF diet. Because previous research indicates that exercise activates the hypothalamic-pituitary-adrenal axis and increases circulating levels of corticosterone, this study tested the hypothesis that elevation of circulating corticosterone is involved in wheel running-induced reduction in HF diet preference in rats.Experiment 1 measured plasma corticosterone levels under sedentary and wheel-running conditions in the two-diet-choice (high-carbohydrate chow vs. HF) feeding regimen. The results revealed that plasma corticosterone is significantly increased and positively correlated with the levels of running in wheel-running rats with two-diet choice.Experiments 2 and 3 determined whether elevated corticosterone without wheel running is sufficient to reduce HF diet intake and preference. Corticosterone was elevated by adding it to the drinking water. Compared with controls, corticosterone-drinking rats had reduced HF diet intake and body weight, but the HF diet preference between groups did not differ. The results of this study support a role for elevated corticosterone on the reduced HF diet intake during wheel running. The elevation of corticosterone alone, however, is not sufficient to produce a robust reduction in HF diet preference.

Role of glucocorticoid signaling in exercise-associated changes in high-fat diet preference in rats

“…Given that WR activates the HPA axis (10,22), it was of interest to examine whether the amount of running influenced Fig. 6.…”

“…Exercise is a physiological challenge that activates the HPA axis (10,34). HPA axis activation results in a signaling cascade that begins in the paraventricular nucleus of the hypothalamus (PVN) and ends with the release of glucocorticoids (GCs) by the adrenal glands into circulation (i.e., corticosterone in rats).…”

“…While multiple studies have shown that GCs can modulate food preference (3,(15)(16)(17)41), there is a lack of consensus in the literature in regard to the effect of GCs on macronutrient selection in intact and adrenalectomized (ADX) rats. One study found that increasing circulating corticosterone (CORT) via drinking water reduced HF diet intake, but not preference, in intact male rats (10). In contrast, other studies have found that GCs increase fat intake and storage (17,41).…”

“…Taken together, these results suggest that adaptation to stressors may be brain region dependent. Given that exercise activates the HPA axis and increases CORT (10,22), GC signaling may influence macronutrient selection while running. Following long-term running, HPA axis adaptation and subsequent changes in HF diet intake may alter central region-specific GC signaling, such as glucocorticoid receptor (GR) trafficking.…”

The Metabolic Implications of Glucocorticoids in a High-Fat Diet Setting and the Counter-Effects of Exercise

“…An interesting aspect to this study was that these results were exercise volume specific, as less running correlated with a reduced amount of metabolic improvements, highlighting the fact that exercise-induced adaptations depend on the duration, intensity, and overall volume of the exercise intervention. Another study investigated the effect of Cort provision during voluntary wheel running on HFD preference [115]. Sprague-Dawley rats that were provided Cort in their drinking water had reduced HFD intake and body weight during wheel running, but interestingly no change in HFD preference.…”