Ultrastructural and biochemical changes in brown fat in cold-exposed rats.
Ultrastructural and biochemical changes in brown fat in cold-exposed rats.
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DOI：
10.1083/jcb.41.1.312
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发表时间：
1969-04
期刊：
影响因子：
--
通讯作者：
Beetham KL
中科院分区：
文献类型：
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作者：
Thomsom JF;Habeck DA;Nance SL;Beetham KL
在大鼠暴露于 5°C 的前 3 天，肩胛间棕色脂肪的氮浓度增加了 50%，并在 8 周的观察期内保持在这一升高水平，而组织质量增加了四倍。单位氮中DNA和RNA的浓度在3天后达到最大值，然后下降；然而，每种产品的总量仍在继续上升。各种呼吸酶的浓度在最初几天下降，然后增加，但速度不同。观察到冷驯化期间成熟棕色脂肪细胞的形态变化为：在冷驯化的前3天内，脂肪滴尺寸减小，随后在冷驯化6周内尺寸逐渐增大；前 3 周内线粒体间基质的量持续增加，1 周后颗粒度和糖原含量增加；线粒体之间的糖原最初消失，随后在寒冷中 1 周后，线粒体间基质中重新出现一些孤立的颗粒；前 3-4 天线粒体内基质密度最初增加，随后逐渐恢复至对照密度；前 4 天内线粒体外膜完整性丧失，随后逐渐但不完全恢复；在最初的 24 小时内，脂滴中的致密物质暂时损失，在寒冷中 1 周后恢复；线粒体直径在 1 天内增加 40%，随后在 1 周内直径减小至比对照大约 15% 的恒定值。
During the first 3 days of exposure of rats to 5°C, the nitrogen concentration of interscapular brown fat increased by 50% and remained at this elevated level for the duration of the 8-wk observation period, while the mass of tissue increased fourfold. The concentration of both DNA and RNA per unit nitrogen reached a maximum after 3 days, then declined; however, the total quantity of each continued to rise. The concentration of various respiratory enzymes decreased during the first few days and then increased, but at different rates. The morphological changes in mature brown fat cells during cold acclimation were observed to be: a reduction in fat droplet size during the first 3 days, followed by a gradual increase in size through 6 wk in the cold; a continual increase in the amount of intermitochondrial ground substance during the first 3 wk, with increased granularity and glycogen content after 1 wk; initial disappearance of glycogen between mitochondria, followed by the reappearance of a few isolated particles in the intermitochondrial ground substance after 1 wk in the cold; initial increase in the density of intramitochondrial matrix for the first 3–4 days, followed by a gradual return to the control density; loss in integrity of mitochondrial outer membranes during the first 4 days, followed by gradual but incomplete restoration; temporary loss of the dense material in lipid droplets during the first 24 hr, with return after 1 wk in the cold; and a 40% increase in mitochondrial diameter within 1 day, followed by a decrease in diameter within 1 wk to a constant value about 15% larger than the controls.