MSG-obesity onset is associated with disruption of central control of the hypothalamus-pituitary-adrenal axis and autonomic nervous system.
J Neuroendocrinol. 2019 Mar 31:e12717. Epub 2019 Mar 31. PMID: 30929305
BACKGROUND/AIMS: The hypothalamic-pituitary-adrenal axis (HPA) exerts important catabolic peripheral effects and influences autonomic nervous system (ANS)-mediated processes. Impaired negative feedback control or reduced HPA axis sensitivity and altered ANS activity seem to be associated with the development and maintenance of obesity. In the present study, we examined the hypothesis that the central HPA axis is dysregulated favoring ANS disbalance in monosodium L-glutamate (MSG)-induced rat obesity.
METHODS: Glucose homeostasis, corticosterone, leptin, and ANS electrical activity were evaluated.
RESULTS: Adult MSG-induced obese rats exhibited fasting hyperinsulinemia, insulin resistance, glucose intolerance, hypercorticosteronemia, hyperleptinemia, and altered ANS activity. A decrease in food intake was observed during corticotrophin-releasing hormone (CRH) treatment in both Control and MSG-treated rats. In contrast, food intake was significantly elevated in control rats treated with dexamethasone (DEXA), while no alterations were observed following DEXA treatment in MSG-induced obese rats. After DEXA injection, an increase in fasting insulin and glucose levels, associated with insulin resistance, was seen in both groups. As expected, there was a decrease of parasympathetic and increase of sympathetic nervous activity in CRH-treated control animals and the opposite effect was seen after DEXA treatment. In contrast, there was no effect on ANS activity in MSG-rats treated with CRH or DEXA.
CONCLUSION: In conclusion, impairment of the HPA axis can lead to disbalance of ANS activity in MSG-treated rats, contributing to the establishment and maintenance of obesity. This article is protected by copyright. All rights reserved.