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| ID: | 101 | | Title: | Hypoxic stimulus alters hypothalamic amp-activated protein kinase phosphorylation concomitant to hyp - http://jap.physiology.org/cgi/content/abstract/102/6/2135?rss=1 | | Description: | Acute exposure to hypobaric hypoxia is known to decrease food intake, but the molecular mechanisms of such alteration in feeding behavior remain unknown. We tested the hypothesis that hypothalamic AMP-activated protein kinase (AMPK) phosphorylation is affected by acute exposure to hypobaric hypoxia and thus would be involved in initial anorexia. To address this issue, male rats weighing 255–270 g were either submitted to hypobaric hypoxia (H, equivalent altitude of 5,500 m), maintained under local barometric pressure conditions (N), or pair-fed an equivalent quantity of food to that consumed by H rats (PF), for 6, 24, or 48 h. Daily food intake dropped by 73% during the first day of hypoxia (P < 0.01) and remained by 46% lower than in N rats thereafter (P < 0.01). Hypoxia per se, as estimated by comparing experimental data between the H and PF groups, increased ob gene transcription and plasma leptin concentration. A transient increase in glucose availability occurred in the H group compared with PF animals (P < 0.05). The hypoxic stimulus led to an early and transient decrease in hypothalamic AMPK and acetyl-CoA carboxylase (ACC) phosphorylation, concomitant with hypophagia and associated alterations in nutrients and hormones. An increase in NPY mRNA levels occurred from day 1, similarly in H and PF rats, and thus mainly related to food restriction alone (P < 0.05). In conclusion, the present study demonstrates that hypoxia per se inhibited AMPK and ACC phosphorylation in the hypothalamus, concomitant with profound anorexia. A powerful counterregulation occurs rapidly, mediated by NPY and devoted to avoid prolonged anorexia. (Source: Journal of Applied Physiology) | | Category: | Anorexia Nervosa | | Link Owner: | | | Date Added: | June 06, 2007 06:34:58 AM | | Number Hits: | 0 | | |
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