LIPOLYTIC AND KETOGENIC FLUXES IN HUMAN HYPERTHYROIDISM
LIPOLYTIC AND KETOGENIC FLUXES IN HUMAN HYPERTHYROIDISM
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DOI：
10.1210/jcem-73-1-42
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发表时间：
1991-07-01
影响因子：
5.8
通讯作者：
MORNEX, R
中科院分区：
文献类型：
--
作者：
BEYLOT, M;MARTIN, C;MORNEX, R
甲状腺功能亢进症对脂解和生酮通量的影响通过同时测量（稳定同位素方法）甘油、非酯化脂肪酸（NEFA）和酮体（KB）动力学在甲状腺功能正常和甲状腺功能亢进受试者中确定。在吸收后状态下，甲亢患者的胰岛素和胰高血糖素浓度正常，但甘油、NEFA和KB的浓度（P <0.01）和转换率（P < 0.01）升高。甲状腺功能亢进患者的NEFA出现率与甘油出现率的比值降低（2.34 +/- 0.23 vs. 3.15 +/- 0.22; P < 0.05），表明甘油三酯和脂肪酸之间的细胞内循环增加。根据NEFA消失率和KB出现率计算，用于KB产生的NEFA流量百分比在甲亢患者中增加（21.20 +/- 2.75%对13.37 +/- 0.63%; P < 0.05），表明甲亢期间肝脂肪酸代谢转向生酮。然而，当对照组受试者的血浆NEFA水平通过输注甘油三酯乳剂升高至与甲亢患者中观察到的水平相当时，其用于生酮的NEFA流量百分比升高至略高于甲亢受试者的值（26.30%）。总之，1）甲状腺功能亢进症不仅导致脂解增加，而且还导致脂肪酸-脂肪酸循环增强，这可能导致过度的能量消耗;和2）甲状腺功能亢进症患者KB产生的增加更多地来自NEFA可用性的增加，而不是直接刺激肝生酮。
The effect of hyperthyroidism on lipolytic and ketogenic fluxes was determined by measuring simultaneously (stable isotope methodology) glycerol, nonesterified fatty acids (NEFA), and ketone body (KB) kinetics in euthyroid and hyperthyroid subjects. In the postabsorptive state hyperthyroid patients had normal concentrations of insulin and glucagon, but increased concentrations (P < 0.01) and turnover rates (P < 0.01) of glycerol, NEFA, and KB. The ratio of NEFA appearance rate to glycerol appearance rate was decreased in hyperthyroid subjects (2.34 +/- 0.23 vs. 3.15 +/- 0.22; P < 0.05), indicating that intracellular cycling between triglycerides and fatty acids was increased. The percentage of NEFA flux used for KB production, calculated from NEFA disappearance rates and KB appearance rates, was increased in hyperthyroid patients (21.20 +/- 2.75% vs. 1 3.37 +/- 0.63%; P < 0.05), suggesting a diversion during hyperthyroidism of hepatic fatty acid metabolism toward ketogenesis. However, when the plasma NEFA levels of control subjects were raised by the infusion of a triglyceride emulsion to levels comparable to those observed in hyperthyroid patients their percentage of NEFA flux used for ketogenesis rose to values slightly higher (26.30%) than those of hyperthyroid subjects. In conclusion, 1) hyperthyroidism results not only in increased lipolysis, but also in enhanced triglyceride-fatty acid cycling, which could contribute to the excessive energy expenditure; and 2) the increased KB production of hyperthyroid patients results more from an increase in NEFA availability than from a direct stimulation of hepatic ketogenesis.