Jungalwala F B, Koul O, Stoolmiller A, Sapirstein V S
J Neurochem. 1985 Jul;45(1):191-8. doi: 10.1111/j.1471-4159.1985.tb05492.x.
Mouse oligodendroglioma cells, G-26 clone 20 and 24, contain galactosylceramide (cerebroside) and sulfogalactosylceramide (sulfatide) as determined by an HPLC technique. The synthesis of both these lipids was stimulated by 10(-6) M hydrocortisone (cortisol) and also by the removal of serum from the culture medium. Forty-eight hours after the addition of cortisol the incorporation of H235SO4 into sulfatide, the level of sulfatide and the specific activity of the enzyme 3'-phosphoadenosine 5'-phosphosulfate:galactosylceramide sulfotransferase in the cells increased three- to fourfold. The level of cerebroside and the specific activity of UDP-galactose:hydroxyacyl sphingosine galactosyltransferase also increased threefold in the cells on treatment with cortisol. The effect of the hormone on the synthesis of cerebroside preceded the increase in sulfatide synthesis. Experiments with cycloheximide and actinomycin D showed that the effect of the hormone on glycolipid synthesis in these cells were mediated through de novo messenger RNA and protein synthesis. Removal of serum from the culture medium resulted in an approximately twofold enhancement of H235SO4 incorporation into sulfatide within 24 h. The levels of sulfatide and cerebroside and the specific activity of the galactosyltransferase and sulfotransferase also increased significantly after serum removal. However, in contrast to the effect of the steroid, the sulfotransferase activity and the level of sulfatide increased prior to elevations in galactosyltransferase and cerebroside. The effect of serum removal was also found to be mediated by de novo RNA and protein synthesis. The effects of cortisol and serum removal on the synthesis of cerebroside and sulfatide were strictly additive.
通过高效液相色谱技术测定，小鼠少突胶质细胞瘤细胞系G - 26克隆20和24含有半乳糖基神经酰胺（脑苷脂）和硫酸半乳糖基神经酰胺（硫脂）。这两种脂质的合成受到10⁻⁶ M氢化可的松（皮质醇）的刺激，同时也受到从培养基中去除血清的刺激。添加皮质醇48小时后，细胞中³⁵SO₄²⁻掺入硫脂的量、硫脂水平以及3'-磷酸腺苷5'-磷酸硫酸酯：半乳糖基神经酰胺硫酸转移酶的比活性增加了三到四倍。用皮质醇处理细胞后，脑苷脂水平和UDP - 半乳糖：羟酰基鞘氨醇半乳糖基转移酶的比活性也增加了三倍。激素对脑苷脂合成的影响先于硫脂合成的增加。用环己酰亚胺和放线菌素D进行的实验表明，激素对这些细胞中糖脂合成的影响是通过从头合成信使核糖核酸和蛋白质介导的。从培养基中去除血清在24小时内使³⁵SO₄²⁻掺入硫脂的量增加了约两倍。去除血清后，硫脂和脑苷脂水平以及半乳糖基转移酶和硫酸转移酶比活性也显著增加。然而，与类固醇的作用相反，硫酸转移酶活性和硫脂水平在半乳糖基转移酶和脑苷脂升高之前就增加了。还发现去除血清的作用也是由从头合成RNA和蛋白质介导的。皮质醇和去除血清对脑苷脂和硫脂合成的影响是严格相加的。
