Gianotti M, Clapés J, Lladó I, Palou A
Departament de Biologia Fonamental i Ciències de la Salut, Universitat de les Illes Balears, Palma de Mallorca, Spain.
Life Sci. 1998;62(20):1889-99. doi: 10.1016/s0024-3205(98)00153-2.
The aim of the present work was to study the effects of various durations of fasting (12, 24 and 72 hours) on brown adipose tissue (BAT) thermogenic parameters--cytrochrome-c-oxidase (COX) activity, GDP-binding activity and uncoupling protein (UCP1) content--and also on morphological features of different mitochondrial subpopulations, obtained by differential centrifugation--M1 (1000 g), M3 (3000 g) and M15 (15,000 g) fractions. The mitochondrial subpopulations showed morphological differences and a different distribution of UCP1 levels and of GDP-binding in all experimental groups. Starvation induced a decrease in the average size for all mitochondrial subtypes. The main changes induced by fasting in thermogenic parameters were observed in the M15 subtype. After the first 24h of starvation, there was a significant decrease of UCP1 levels only in the lightest mitochondrial subpopulation. However, the 72h fasted situation reflected a tendency to increase UCP1 content and UCP1/COX ratio together with a significant decrease of GDP-binding/UCP1 ratio, thus indicating more masked GDP-binding sites. Important fasting-induced changes in both morphological and biochemical parameters in BAT mitochondrial subtypes reflect their role in the physiological response of BAT to starvation.
本研究的目的是探讨不同禁食时长（12小时、24小时和72小时）对棕色脂肪组织（BAT）产热参数的影响，这些参数包括细胞色素c氧化酶（COX）活性、GDP结合活性和解偶联蛋白（UCP1）含量，同时研究禁食对通过差速离心获得的不同线粒体亚群形态特征的影响，这些亚群包括M1（1000g）、M3（3000g）和M15（15000g）组分。在所有实验组中，线粒体亚群均表现出形态差异以及UCP1水平和GDP结合的不同分布。饥饿导致所有线粒体亚型的平均大小减小。禁食对产热参数的主要影响在M15亚型中最为明显。饥饿24小时后，仅在最轻的线粒体亚群中观察到UCP1水平显著下降。然而，禁食72小时的情况表明，UCP1含量和UCP1/COX比值有增加的趋势，同时GDP结合/UCP1比值显著下降，这表明GDP结合位点被更多地掩盖。禁食诱导的BAT线粒体亚型形态和生化参数的重要变化反映了它们在BAT对饥饿的生理反应中的作用。
