Jourdan M L, Wang L C, Christopherson R J
Life Sci. 1984 Mar 19;34(12):1101-9. doi: 10.1016/0024-3205(84)90080-8.
In an attempt to further elucidate the mechanisms of fasting-depressed maximum thermogenesis and cold tolerance, norepinephrine (NE)-stimulated non-shivering thermogenesis (NST) in cold-acclimated rats was used as a functional index of possible alterations in adrenergic efficacy after fasting. Fasting decreased the magnitude of maximum NE-Stimulated NST by 18.2% [6.87 +/- 0.47 Kcal (Kg X 75 X min)-1 well-fed vs. 5.81 +/- 0.39 Kcal (Kg X 75 X min)-1 fasted], but the apparent adrenergic binding affinity was not affected [Ke = 0.43 micrograms NE min-1 well-fed vs. 0.55 micrograms NE min-1 fasted]. Pretreatment with aminophylline [15 mg Kg-1, i.p.], a phosphodiesterase inhibitor, restored the fasting-depressed NE-stimulated NST to the fed level. The results suggest that the depression of maximum thermogenesis after fasting is not due to changes in adrenergic binding characteristics but to alteration in cAMP production/degradation, resulting in decreased substrate mobilization for thermogenesis.
为了进一步阐明禁食导致最大产热和耐寒能力降低的机制，将去甲肾上腺素（NE）刺激的冷适应大鼠非颤抖产热（NST）作为禁食后肾上腺素能功效可能改变的功能指标。禁食使最大NE刺激的NST幅度降低了18.2%[饱食组为6.87±0.47千卡/（千克×75×分钟），禁食组为5.81±0.39千卡/（千克×75×分钟）]，但表观肾上腺素能结合亲和力未受影响[饱食组的Ke=0.43微克NE/分钟，禁食组为0.55微克NE/分钟]。用磷酸二酯酶抑制剂氨茶碱[15毫克/千克，腹腔注射]预处理可将禁食导致的NE刺激的NST恢复到进食水平。结果表明，禁食后最大产热的降低不是由于肾上腺素能结合特性的改变，而是由于环磷酸腺苷（cAMP）产生/降解的改变，导致产热的底物动员减少。
