Jackson J M, Lee H A
Department of Renal and Metabolic Medicine, University of Southampton, United Kingdom.
Am J Clin Nutr. 1996 Dec;64(6):922-7. doi: 10.1093/ajcn/64.6.922.
The effects of the acetate content of hemodialysis fluids on the relation between L-carnitine (free carnitine, cr FC) and acetyl-L-carnitine (AC) have not previously been examined in detail. The net fluxes of FC, AC, and acetate between intra- and extracellular pools during hemodialysis were calculated using a kinetic model with dialysates containing three concentrations of FC (0, 40, and 80 mumol/L) and either 40 or 3 mmol acetate/L. Radioenzymatic assays of FC and AC were optimized for use with samples taken during hemodialysis. Acetate stimulated a tissue uptake of FC (P < 0.05) that could exceed the rate of FC delivery and was related to the dialysate FC composition (P < 0.02). There were associated changes in tissue AC output. With dialysate containing 40 mmol acetate/L, AC tissue output was directly related to the dialysate FC composition (P < 0.05). The AC tissue output was less with dialysate containing 3 mmol acetate/L (P < 0.05) but the significant increase with the provision of FC in the dialysate was retained (P < 0.05). Hemodialysis may therefore represent an acute period of relative carnitine deficiency when regeneration of free coenzyme A from acetyl coenzyme A consequent to metabolism of acetate is limited.
血液透析液中醋酸盐含量对左旋肉碱（游离肉碱，FC）与乙酰左旋肉碱（AC）之间关系的影响，此前尚未进行过详细研究。使用动力学模型计算血液透析期间细胞内和细胞外池之间FC、AC和醋酸盐的净通量，该模型采用含有三种浓度FC（0、40和80 μmol/L）和40或3 mmol/L醋酸盐的透析液。对FC和AC的放射酶法进行了优化，以用于血液透析期间采集的样本。醋酸盐刺激了FC的组织摄取（P < 0.05），其摄取速率可能超过FC的输送速率，并且与透析液中FC的组成有关（P < 0.02）。组织AC输出也有相关变化。对于含有40 mmol/L醋酸盐的透析液，AC组织输出与透析液中FC的组成直接相关（P < 0.05）。对于含有3 mmol/L醋酸盐的透析液，AC组织输出较少（P < 0.05），但透析液中提供FC时仍有显著增加（P < 0.05）。因此，当醋酸盐代谢导致的乙酰辅酶A再生游离辅酶A受限，血液透析可能代表相对肉碱缺乏的急性期。
