High-fat feeding alters both basal and stress-induced hypothalamic-pituitary-adrenal activity in the rat

Abstract

High-fat feeding induces insulin resistance and increases the risk for the development of diabetes and coronary artery disease. Glucocorticoids exacerbate this hyperinsulinemic state, rendering an individual at further risk for chronic disease. The present studies were undertaken to determine whether dietary fat-induced increases in corticosterone (B) reflect alterations in the regulatory components of the hypothalamic-pituitary-adrenal (HPA) axis. Adult male rats were maintained on a high-fat (20%) or control (4%) diet for varying periods of time. Marked elevations in light-phase spontaneous basal B levels were evident as early as 7 days after fat diet onset, and B concentrations remained significantly elevated up to 21 days after fat diet onset compared with controls. In contrast, there were no significant effects on any parameters of spontaneous growth hormone secretory profiles, thus providing support for the specificity of the effects on the HPA axis. In a second study, all groups of rats fed the high-fat diet for 1, 9, or 12 wk exhibited significantly elevated levels of plasma adrenocorticotropic hormone, B, fatty acid, and glucose before, during, and/or at 20, 60, and/or 120 min after the termination of a restraint stress. Furthermore, 12-wk fat-fed animals showed a significant resistance to insulin compared with normally fed controls. There were no differences in negative feedback efficacy in high-fat-fed rats vs. controls. Taken together, these results suggest that dietary fat intake acts as a background form of chronic stress, elevating basal B levels and enhancing HPA responses to stress.

Postnatal Programming of Glucocorticoid Metabolism in Rats Modulates High-Fat Diet–Induced Regulation of Visceral Adipose Tissue Glucocorticoid Exposure and Sensitivity and Adiponectin and Proinflammatory Adipokines Gene Expression in Adulthood

“…We found that high-fat feeding increased corticosterone production, as demonstrated by the increased urinary corticosterone concentrations. Such stimulation of adrenal glucocorticoid secretion has already been described both in laboratory animals and in humans (22,23). However, high-fat feeding-induced stimulation of systemic glucocorticoid levels was comparable in control and programmed animals, suggesting that the potentiation of adipose tissue deposition and metabolic alterations induced by high-fat diet in programmed rats was not subsequent to the increase in circulating glucocorticoids.…”

The effects of diet composition and ration on biotransformation enzymes and stress parameters in rainbow trout, Oncorhynchus mykiss

“…Basal corticosterone levels were shown not to be affected in rats fed high fat diets (59% of calories) as compared to high starch diets (70% of calories) by Pascoe et al (1991), while Tannenbaum et al (1997) showed that rats fed diets high in fat (20%) had significantly elevated corticosterone levels as compared to rats fed control diets (5% fat).…”

Prenatal nicotine exposure enhances the susceptibility to metabolic syndrome in adult offspring rats fed high-fat diet via alteration of HPA axis-associated neuroendocrine metabolic programming

“…These results suggested that PNE enhanced the sensitivity of the HPA axis to chronic stress. Moreover, a high-fat diet can also increase the release of ACTH and CORT after stress in adult rats [40] . Therefore, in the present study, the enhanced sensitivity of the HPA axis to chronic stress in adult offspring might result from the potentiation of PNE and the postnatal high-fat diet.…”