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In rats that were fasted for 2 to 3 days there was a decline in hypothalamic, but not pituitary, beta-endorphin. There was no change in pituitary or hypothalamic adrenocorticotropin content as a result of fasting. Endogenous opiates may be involved in physiological adaptation to fasting.
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Gambert et al. (1980) studied this question.
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