Sucrose ingestion normalizes central expression of corticotropin-releasing-factor messenger ribonucleic acid and energy balance in adrenalectomized rats: A glucocorticoid-metabolic-brain axis?

Both CRF and norepinephrine (NE) inhibit food intake and stimulate ACTH sec retion and sympathetic outflow. CRF also increases anxiety; NE increases at tention and cortical arousal. Adrenalectomy (ADX) changes CRF and NE activi ty in brain, increases ACTH secretion and sympathetic outflow and reduces f ood intake and weight gain; all of these effects are corrected by administr ation of adrenal steroids. Unexpectedly, we recently found that ADX rats dr inking sucrose, but not saccharin, also have normal caloric intake, metabol ism, and ACTH. Here, we show that ADX (but not sham-ADX) rats prefer to con sume significantly more sucrose than saccharin. Voluntary ingestion of sucr ose restores CRF and dopamine-P-hydroxylase messenger RNA expression in bra in, food intake, and caloric efficiency and fat deposition, circulating tri glyceride, leptin, and insulin to normal. Our results suggest that the brai ns of ADX rats, cued by sucrose energy (but not by nonnutritive saccharin) maintain normal activity in systems that regulate neuroendocrine (hypothala mic-pituitary-adrenal), behavioral (feeding), and metabolic functions (fat deposition). We conclude that because sucrose ingestion, like glucocorticoi d replacement, normalizes energetic and neuromodulatory effects of ADX, man y of the actions of the steroids on the central nervous system under basal conditions may be indirect and mediated by signals that result from the met abolic effects of adrenal steroids.