Shen G X, Angel A
Department of Internal Medicine, University of Manitoba, Winnipeg, Canada.
Am J Physiol. 1995 Jul;269(1 Pt 1):E99-107. doi: 10.1152/ajpendo.1995.269.1.E99.
The present study demonstrates cholesteryl ester transfer activity (CETA) in cultured hamster and rat adipose tissue. Cultured hamster and rat adipose tissue fragments released CETA into the conditioned medium, and this was associated with a reciprocal decrease in adipose tissue CETA. Regional variations in adipose CETA were observed. The levels of CETA released from cultured hamster and rat adipocytes were higher than those from adipose tissue fragments. In hamsters but not in rats, the secretion of CETA from cultured adipose tissue was increased by insulin and inhibited by EDTA in a dose-dependent fashion. Monoclonal antibodies against human cholesteryl ester transfer protein inhibited the CETA secreted from hamster adipose tissue but not that from rat adipose tissue. Fasting for 24 h and a high-cholesterol saturated fat-rich diet increased adipose CETA in hamsters and rats, and this was associated with an elevation of plasma CETA only in hamsters. This supports the view that, in hamsters, adipose CETA has in situ and intravascular functions, whereas in rats the role of adipose CETA is restricted to tissue-specific functions. Hamster cholesteryl ester transfer protein may differ from rat adipose-associated CETA in the structure of the active site and the regulatory mechanism for its secretion.
本研究证实了培养的仓鼠和大鼠脂肪组织中存在胆固醇酯转移活性（CETA）。培养的仓鼠和大鼠脂肪组织碎片将CETA释放到条件培养基中，这与脂肪组织CETA的相应降低有关。观察到脂肪组织CETA存在区域差异。培养的仓鼠和大鼠脂肪细胞释放的CETA水平高于脂肪组织碎片。在仓鼠中而非大鼠中，培养的脂肪组织分泌CETA受胰岛素以剂量依赖方式增加，受EDTA抑制。抗人胆固醇酯转移蛋白单克隆抗体抑制仓鼠脂肪组织分泌的CETA，但不抑制大鼠脂肪组织分泌的CETA。禁食24小时和高胆固醇饱和脂肪丰富的饮食会增加仓鼠和大鼠的脂肪组织CETA，而这仅在仓鼠中与血浆CETA升高有关。这支持了以下观点：在仓鼠中，脂肪组织CETA具有原位和血管内功能，而在大鼠中，脂肪组织CETA的作用仅限于组织特异性功能。仓鼠胆固醇酯转移蛋白在活性位点结构及其分泌调节机制方面可能与大鼠脂肪相关CETA不同。
