Heikkilä P, Kahri A I, Ehnholm C, Kovanen P T
Department of Pathology, University of Helsinki, Finland.
Cell Tissue Res. 1989 Jun;256(3):487-94. doi: 10.1007/BF00225596.
We studied the effects of lipoprotein-derived cholesterol on the ACTH-induced differentiation of cultured fetal rat adrenocortical cells. For this purpose human plasma high-density lipoprotein3 (HDL3) or low-density lipoprotein (LDL) was added to culture media devoid of cholesterol, and thereafter the morphological changes in cells were monitored and the amounts of steroids synthesized were measured. It could be demonstrated that, ultrastructurally, upon ACTH-stimulation the adrenocortical cells differentiated into fasciculata-like cells even in the absence of lipoproteins in the culture medium. The addition of either HDL3 or LDL caused an increase in the number and size of cytoplasmic lipid droplets suggesting uptake and deposition of lipoprotein-derived cholesterol into the differentiating cells. The amount of steroids secreted from cells differentiating in media devoid of cholesterol was only half that observed in cells differentiating in serum-supplemented medium. Addition of either HDL3 or LDL increased the ACTH-stimulated steroid synthesis to the levels observed in serum-supplemented medium. This study demonstrates that both HDL3 and LDL are able to provide cholesterol for steroid synthesis accompanying the ACTH-induced differentiation of fetal rat adrenocortical cells.
我们研究了脂蛋白衍生胆固醇对促肾上腺皮质激素（ACTH）诱导的培养胎鼠肾上腺皮质细胞分化的影响。为此，将人血浆高密度脂蛋白3（HDL3）或低密度脂蛋白（LDL）添加到不含胆固醇的培养基中，然后监测细胞的形态变化并测量合成的类固醇量。结果表明，在超微结构上，即使培养基中不存在脂蛋白，在ACTH刺激下肾上腺皮质细胞也会分化为束状带样细胞。添加HDL3或LDL都会导致细胞质脂滴数量和大小增加，表明脂蛋白衍生的胆固醇被摄取并沉积到分化细胞中。在不含胆固醇的培养基中分化的细胞分泌的类固醇量仅为在补充血清的培养基中分化的细胞中观察到的一半。添加HDL3或LDL均可将ACTH刺激的类固醇合成增加到在补充血清的培养基中观察到的水平。这项研究表明，HDL3和LDL都能够为伴随ACTH诱导的胎鼠肾上腺皮质细胞分化的类固醇合成提供胆固醇。
