TY - JOUR
T1 - Brown fat GDP binding and circulating metabolites during hibernation and arousal
AU - Nizielski, S. E.
AU - Billington, C. J.
AU - Levine, Allen S
PY - 1989
Y1 - 1989
N2 - The effect of hibernation and arousal on brown adipose tissue (BAT) cytochrome-c oxidase activity and GDP binding, as well-circulating metabolites, have been studied in the 13-lined ground squirrel. Control animals (warm adapted) were housed continuously at 23°C, while the remaining animals were transferred into a cold room (4°C) for 8 days to induce hibernation. Hibernating animals were killed with deeply hibernating. Aroused animals were manually stimulated to induce arousal or had spontaneously aroused on the day of the experiment. BAT weight as well as mitochondrial mass were increased in both groups of cold-adapted animals, relative to controls. A substantial increase in GDP binding, however, was seen only in aroused animals, an observation confirmed by Scatchard analysis. Arousal was also accompanied by marked alterations in the levels of several circulating metabolites. Plasma free fatty acids declined by ~ 20% despite a three- to fourfold increase in plasma glycerol concentrations. Plasma lactate levels increased eightfold, while concentrations of β-hydroxybutyrate were five times lower during arousal than hibernation. These data are consistent with the idea that the oxidation of free fatty acids, glucose, and ketone bodies are all increased during arousal. In conclusion, we have found that cold adaptation and subsequent hibernation increases BAT thermogenic capacity in the 13-lined ground squirrel. However, this increase in thermogenic potential is not manifested as a substantial increase in BAT thermogenic activity until arousal is initiated.
AB - The effect of hibernation and arousal on brown adipose tissue (BAT) cytochrome-c oxidase activity and GDP binding, as well-circulating metabolites, have been studied in the 13-lined ground squirrel. Control animals (warm adapted) were housed continuously at 23°C, while the remaining animals were transferred into a cold room (4°C) for 8 days to induce hibernation. Hibernating animals were killed with deeply hibernating. Aroused animals were manually stimulated to induce arousal or had spontaneously aroused on the day of the experiment. BAT weight as well as mitochondrial mass were increased in both groups of cold-adapted animals, relative to controls. A substantial increase in GDP binding, however, was seen only in aroused animals, an observation confirmed by Scatchard analysis. Arousal was also accompanied by marked alterations in the levels of several circulating metabolites. Plasma free fatty acids declined by ~ 20% despite a three- to fourfold increase in plasma glycerol concentrations. Plasma lactate levels increased eightfold, while concentrations of β-hydroxybutyrate were five times lower during arousal than hibernation. These data are consistent with the idea that the oxidation of free fatty acids, glucose, and ketone bodies are all increased during arousal. In conclusion, we have found that cold adaptation and subsequent hibernation increases BAT thermogenic capacity in the 13-lined ground squirrel. However, this increase in thermogenic potential is not manifested as a substantial increase in BAT thermogenic activity until arousal is initiated.
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M3 - Article
C2 - 2782456
AN - SCOPUS:0024367107
SN - 0002-9513
VL - 257
SP - 26/3
JO - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
JF - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
IS - 3
ER -