Levin B E, Comai K, O'Brien R A, Sullivan A C
Am J Physiol. 1982 Sep;243(3):E217-24. doi: 10.1152/ajpendo.1982.243.3.E217.
The composition, morphology, beta-adrenergic receptor binding, and in vitro lipolysis were examined in lean and obese, 5- to 6-mo-old male Zucker rat interscapular brown adipose tissue (IBAT). IBAT pads from obese rats were heavier (283%), had more lipid (700%), and more (75%)( and larger (83%) adipocytes than those from lean rats. Also, IBAT from obese rats had no multiloculated cells, and 50% of their IBAT adipocytes were the size of white fat cells. High affinity binding for (-)-[3H]dihydroalprenolol (KD, 15-18 nM), as well as the estimated KD values for binding and the 1/2 Vmax values for adrenergic agonist-induced lipolysis were similar in isolated IBAT cells from lean and obese rats. However, adipocytes from IBAT in obese rats had 75% fewer high affinity beta-adrenergic binding sites per cell (Bmax) compared to those in lean rats. These findings are most compatible with the infiltration of IBAT by white adipocytes. Such infiltration would be expected to reduce the overall thermogenic capacity of IBAT in obese Zucker rats and thereby contribute to the maintenance of their obesity.
对5至6月龄雄性瘦型和肥胖型 Zucker 大鼠的肩胛间棕色脂肪组织（IBAT）的组成、形态、β-肾上腺素能受体结合情况及体外脂肪分解进行了检测。肥胖大鼠的IBAT垫更重（重283%），脂质更多（多700%），脂肪细胞数量更多（多75%）且更大（大83%），与瘦型大鼠相比。此外，肥胖大鼠的IBAT没有多房性细胞，其IBAT脂肪细胞中有50%的大小与白色脂肪细胞相同。在瘦型和肥胖型大鼠分离的IBAT细胞中，对（-）-[3H]二氢阿普洛尔的高亲和力结合（KD，15 - 18 nM）以及结合的估计KD值和肾上腺素能激动剂诱导的脂肪分解的1/2 Vmax值相似。然而，与瘦型大鼠相比，肥胖大鼠IBAT中的脂肪细胞每细胞的高亲和力β-肾上腺素能结合位点（Bmax）少75%。这些发现与白色脂肪细胞浸润IBAT最为相符。这种浸润预计会降低肥胖 Zucker 大鼠IBAT的整体产热能力，从而导致其肥胖状态的维持。
