Proliferation and function of fat cells of the obese in tissue: Fundamental research of the obesity

成熟的白色脂肪细胞（单眼脂肪细胞）通常被认为处于终末分化，因此没有增殖能力。我们实验室设计了一种在体外培养单眼脂肪细胞的新方法，称为“天花板培养”。在这种培养条件下，脂肪细胞继续表现出特定的脂质代谢功能，并广泛增殖。胞浆内脂滴对细胞分裂无抑制作用。有两种扩散模式的单室的脂肪细胞:细胞分裂“loculus-dividing”,的单胞分裂细胞的脂肪分解成多个液滴和均匀分布之间的子细胞,和loculus-preserving”细胞分裂,分裂细胞的胞是最小分解保存和继承其形状的子细胞与其他得到只有少量脂滴。这些发现表明，体内的单眼脂肪组织在某些条件下可能能够在这种模式下增殖。有了这样的结果，我们在培养条件下检查了肥胖的脂肪细胞。首先，胰岛素是一种脂质因子，是肥胖的主要因素之一。因此，胰岛素对脂肪细胞的“保室”细胞分裂与肥胖者的高胰岛素血症是相容的。其次，来源于肥胖者的单眼大脂肪细胞在培养条件下也能增殖。我们希望这里描述的培养系统将在脂肪细胞生物学和肥胖机制的研究中有价值。

Mature white fat cells (unilocular fat cells) have generally been consifered to be in terminal differentiation and, hence, to have no proliferative ability. A new method, referred to as "ceiling culture", has been devised in our laboratory to culture unilocular fat cells in vitro. Under such culture conditions, the fat cells continue to exhibit specific functions of lipid metabolism and proliferate extensively. Intracytoplasmic lipid droplets did not inhibit division of the cells. There were two modes of proliferation of unilocular fat cells: "loculus-dividing" cell division, in which the single loculus of fat in the dividing cell was broken down into multiple droplets and distributed evenly between the daughter cells, and loculus-preserving" cell division, in which the loculus in the dividing cell was minimally broken down and inherited with its shape preserved by one of the daughter cells with the other getting only a small number of fine lipid droplets. Such findings suggest that unilocular fat tissue in vivo are probably capable of proliferation in such modes under some conditions. With such results, fat cells of the obese was examined under the culture condition. First, insulin which is a lipogenie factor is one of the major factors of obesity. Therefore, "loculus-preserving" cell division of fat cells by insulin is compatible with the hyperinsulinemia of the obese. Secondly, large unilocular fat cells derived from the obese could also proliferate under the culture condition.We hope that the culture system described here will be valuable in studies of the biology of fat cells and the mechanism of obesity.