Peripheral and Central Glucocorticoid Signaling Contributes to Positive Energy Balance in Rats

The obesity epidemic has been the target of several studies to understand its etiology. The pathophysiological processes that take to obesity generally relate to the rupture of energy balance. This imbalance can result from environmental and/or endogenous events. Among the endogenous events, the hypothalamic-pituitary-adrenal axis, which promotes stress response via glucocorticoid activity, is considered a modulator of energy balance. However, it remains controversial whether the increase in plasma levels of glucocorticoids results in a positive or negative energy balance. Furthermore, there are no studies comparing different routes of administration of glucocorticoids in this context. Here, we investigated the effects of intraperitoneal (i.p.) or intracerebroventricular (i.c.v.) administration of a specific agonist for glucocorticoid receptors on food intake and energy expenditure in rats. Sixty-day old rats were treated with i.p. or i.c.v. dexamethasone. Food intake and satiety were evaluated, as well as locomotor activity in order to determine energy expenditure. Both i.p. and i.c.v. dexamethasone increased food intake and decreased energy expenditure. Moreover, i.c.v. dexamethasone delayed the onset of satiety. Together, these results confirm that central glucocorticoid signaling promotes a positive energy balance and supports the role of the glucocorticoid system as the underlying cause of psychological stress-induced obesity.