de Valk H W, Bianchi R, van Rijn H J, Erkelens D W
Department of Internal Medicine, University Hospital Utrecht, The Netherlands.
Clin Chem Lab Med. 1998 Feb;36(2):115-7. doi: 10.1515/CCLM.1998.022.
Plasma non-esterified (free) fatty acid concentrations rise as a consequence of stimulated endogenous lipolysis and are inversely related to the plasma magnesium concentration when plasma adrenaline concentration is increased. The aim of the study was to test whether high plasma non-esterified fatty acid concentration after infusion of non-esterified fatty acids decreases plasma magnesium concentration.
Twelve healthy subjects received 500 ml Intralipid or saline in a randomised, cross-over, double-blind design. Infusion of Intralipid results in an isolated elevation of plasma non-esterified fatty acid concentration. Plasma magnesium concentration was determined at baseline and every 30 minutes; plasma non-esterified fatty acid and triglyceride concentrations at baseline and after 120 minutes.
Initial plasma magnesium, non-esterified fatty acid, and triglyceride concentrations were similar in both groups. A significant increase in plasma non-esterified fatty acids (2.42 +/- 0.96 mmol/l vs 0.58 +/- 0.23 mmol/l, p = 0.00013) and triglyceride (median and 95th percentile 5.36 (7.35) mmol/l vs 1.18 (1.92) mmol/l, p = 0.003) concentrations was seen with Intralipid. Plasma magnesium concentration increased significantly after Intralipid (0.89 +/- 0.09 mmol/l vs 0.81 +/- 0.06 mmol/l, p = 0.007). No significant changes were seen with saline. A positive association was found between the change in plasma magnesium and triglyceride concentrations (r = 0.85, p = 0.001).
Acute infusion of non-esterified fatty acids from an exogenous source does not result in a fall in plasma magnesium concentration, indicating that the circulating non-esterified fatty acids play no part in a decrease in plasma magnesium concentration. The high circulating non-esterified fatty acid levels and the fall in plasma magnesium concentration are both a consequence of intracellular lipolysis.
内源性脂肪分解受刺激会导致血浆非酯化（游离）脂肪酸浓度升高，且当血浆肾上腺素浓度升高时，其与血浆镁浓度呈负相关。本研究的目的是检验输注非酯化脂肪酸后高血浆非酯化脂肪酸浓度是否会降低血浆镁浓度。
12名健康受试者按随机、交叉、双盲设计接受500毫升英脱利匹特或生理盐水。输注英脱利匹特会导致血浆非酯化脂肪酸浓度单独升高。在基线时以及每隔30分钟测定血浆镁浓度；在基线时和120分钟后测定血浆非酯化脂肪酸和甘油三酯浓度。
两组的初始血浆镁、非酯化脂肪酸和甘油三酯浓度相似。输注英脱利匹特后，血浆非酯化脂肪酸（2.42±0.96毫摩尔/升对0.58±0.23毫摩尔/升，p = 0.00013）和甘油三酯（中位数和第95百分位数5.36（7.35）毫摩尔/升对1.18（1.92）毫摩尔/升，p = 0.003）浓度显著升高。输注英脱利匹特后血浆镁浓度显著升高（0.89±0.09毫摩尔/升对0.81±0.06毫摩尔/升，p = 0.007）。输注生理盐水未见显著变化。血浆镁变化与甘油三酯浓度之间存在正相关（r = 0.85，p = 0.001）。
外源性输注非酯化脂肪酸不会导致血浆镁浓度下降，这表明循环中的非酯化脂肪酸在血浆镁浓度降低中不起作用。高循环非酯化脂肪酸水平和血浆镁浓度下降均是细胞内脂肪分解的结果。
