Mølstad P, Bøhmer T
Biochim Biophys Acta. 1979 Jun 1;585(1):94-9. doi: 10.1016/0304-4165(79)90328-3.
Prednisolone (10(-8)--10(-5) mol/l) in the growth medium for 24 h increased the rate of uptake of L-[3H]carnitine in an established cell line (CCL 27) to 164 +/- 6% (mean +/-S.E.) of the rate observed in untreated cells. At the same time the intracellular content of free L-carnitine increased about 20%. The simultaneous addition of prednisolone (10(-6) mol/l for 24 h) and L-carnitine (10(-4) mol/l for 96 h) to the growth medium increased the rate of uptake to 225 +/- 8% (mean +/-S.E.) of that in untreated cells. The increase seemed to be mediated through an increase in number of carriers, as judged by the increase in V of the transport process with unchanged Km. Phosphodiesterase I, an enzyme mainly localized in the plasma membrane, increased its activity about 3.5 times when cells were stimulated with prednisolone. Thus, it seems that the increase in the rate of uptake of L-carnitine mediated by glucocorticoids, is part of a more general effect on the plasma membrane. The observations offer an explanation to the observed clinical improvement in patients with muscular carnitine deficiency treated with glucocorticoids and/or L-carnitine.
在生长培养基中加入泼尼松龙（10⁻⁸ - 10⁻⁵mol/L）24小时，可使一种已建细胞系（CCL 27）中L-[³H]肉碱的摄取速率增加至未处理细胞中观察到速率的164±6%（平均值±标准误）。与此同时，细胞内游离L-肉碱含量增加了约20%。在生长培养基中同时加入泼尼松龙（10⁻⁶mol/L，24小时）和L-肉碱（10⁻⁴mol/L，96小时），摄取速率增加至未处理细胞的225±8%（平均值±标准误）。从转运过程中V增加而Km不变判断，这种增加似乎是通过载体数量增加介导的。磷酸二酯酶I是一种主要定位于质膜的酶，当用泼尼松龙刺激细胞时，其活性增加约3.5倍。因此，糖皮质激素介导的L-肉碱摄取速率增加似乎是对质膜更普遍作用的一部分。这些观察结果为用糖皮质激素和/或L-肉碱治疗的肌肉肉碱缺乏患者所观察到的临床改善提供了解释。
