Alonso-Vale Maria Isabel Cardoso, Anhê Gabriel Forato, Borges-Silva Cristina das Neves, Andreotti Sandra, Peres Sidney Barnabé, Cipolla-Neto José, Lima Fabio Bessa
Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.
Metabolism. 2004 Apr;53(4):500-6. doi: 10.1016/j.metabol.2003.11.009.
This study investigated the effects of pinealectomy and fasting on rat adipose tissue metabolism, as well as on profiles of the hormones directly involved in its regulation (insulin, leptin, and corticosterone). Pinealectomized (PINX) and sham-operated (CONTROL) adult male Wistar rats were killed 6 weeks after surgery, in either fed or fasted (12 and 36 hours) states. Blood samples (for glucose and hormone determinations) and peri-epididymal adipocytes (for in vitro insulin-stimulated glucose uptake, oxidation, and incorporation into lipids) were collected. Pineal ablation decreased insulin-stimulated glucose uptake in adipocytes of both fed and fasted animals without affecting insulin-binding capacity. Pinealectomy attenuated the reduction in the ability to oxidize glucose in both basal and insulin-stimulated states during fasting. This alteration in the ability of adipocytes to oxidize glucose appeared together with a decrease in insulin-induced glucose incorporation into lipids in PINX animals. Additionally, pinealectomized rats showed higher corticosterone levels in both fed and fasted states, and a lower leptinemia with 36 hours of fasting, in comparison to CONTROLs. In conclusion, our data reinforce the hypothesis that the pineal gland has a role in the modulation of adipocyte metabolism, and its absence alters metabolic adaptation to fasting in rats.
本研究调查了松果体切除和禁食对大鼠脂肪组织代谢的影响，以及对直接参与其调节的激素（胰岛素、瘦素和皮质酮）水平的影响。松果体切除（PINX）和假手术（CONTROL）的成年雄性Wistar大鼠在术后6周处死，处于进食或禁食（12小时和36小时）状态。采集血样（用于测定葡萄糖和激素）和附睾周围脂肪细胞（用于体外胰岛素刺激的葡萄糖摄取、氧化以及掺入脂质）。松果体切除降低了进食和禁食动物脂肪细胞中胰岛素刺激的葡萄糖摄取，而不影响胰岛素结合能力。松果体切除减弱了禁食期间基础状态和胰岛素刺激状态下葡萄糖氧化能力的降低。在PINX动物中，脂肪细胞氧化葡萄糖能力的这种改变与胰岛素诱导的葡萄糖掺入脂质的减少同时出现。此外，与对照组相比，松果体切除的大鼠在进食和禁食状态下皮质酮水平均较高，禁食36小时时瘦素血症水平较低。总之，我们的数据支持了这样的假设，即松果体在调节脂肪细胞代谢中起作用，其缺失会改变大鼠对禁食的代谢适应。
