Marcelo A J, Pieringer R A
Department of Biochemistry Temple University, School of Medicine, Philadelphia, Pennsylvania 19140.
Neurochem Res. 1990 Sep;15(9):937-44. doi: 10.1007/BF00965916.
Previous work from our laboratory (Biochem. J. 219:689-697 (1984] had shown that hydrocortisone stimulated the net accumulation of the myelin-specific sulfolipid in cultures of cells dissociated from embryonic mouse cerebra. This accumulation caused by hydrocortisone was shown to be due to a decrease of sulfolipid degradation by arylsulfatase A (ASA) and not due to a stimulation of its synthesis by a sulfotransferase. Both ASA activity and the turnover of sulfolipid were decreased by hydrocortisone to 60-62% of untreated cells. In current work the same decrease in enzyme activity was obtained and enzyme linked immunosorbent assays demonstrate that hydrocortisone decreased the number of ASA protein molecules to 61% of untreated cells [(-)hydrocortisone: 0.31 +/- 0.06 ng ASA/microgram protein; (+)hydrocortisone: 0.18 +/- 0.04 ng ASA/microgram protein]. This decrease in the number of ASA molecules correlates well with the decrease in both the enzyme activity and the sulfolipid turnover, which suggests that the major mode of inhibition of ASA activity by hydrocortisone involves a decrease in the concentration of ASA in the cells rather than some other mechanism of inhibition.
我们实验室先前的研究工作（《生物化学杂志》219:689 - 697 [1984]）表明，氢化可的松能刺激从小鼠胚胎大脑解离的细胞培养物中髓磷脂特异性硫脂的净积累。氢化可的松引起的这种积累被证明是由于芳基硫酸酯酶A（ASA）导致硫脂降解减少，而不是由于磺基转移酶刺激其合成。氢化可的松使ASA活性和硫脂周转率均降至未处理细胞的60 - 62%。在当前的研究中，获得了相同程度的酶活性降低，酶联免疫吸附测定表明，氢化可的松使ASA蛋白分子数量降至未处理细胞的61% [（ - ）氢化可的松：0.31±0.06 ng ASA/微克蛋白；（ + ）氢化可的松：0.18±0.04 ng ASA/微克蛋白]。ASA分子数量的这种减少与酶活性和硫脂周转率的降低密切相关，这表明氢化可的松抑制ASA活性的主要方式涉及细胞中ASA浓度的降低，而不是其他某种抑制机制。
