Sapin R, Schlienger J L, Grunenberger F, Gasser F, Chambron J
Institut de Physique Biologique, Faculté de Médecine, Strasbourg, France.
Clin Chem. 1990 Apr;36(4):611-3.
To compare in vitro and in vivo effects of increased concentrations of free fatty acids (FFA) on free thyroxin (FT4) values, we measured FT4 in three pooled sera supplemented with oleate and in serum from 18 euthyroid patients before and after an infusion of fat emulsion (Intralipid). We used five FT4 RIA kits: two two-step methods [Gammacoat, Baxter (GC); Ria-gnost, Behring (RG)], two analog RIAs [Amerlex-M, Amersham (AM); Coat-Ria, BioMérieux (CR)], and one kit with labeled antibodies [Amerlex-MAB*, Amersham (AA)]. In vitro, at the maximum oleate addition of 5 mmol/L, FT4 increased when measured by the GC and RG kits, decreased by the AM kit, and showed no significant change by the CR and AA kits. In vivo, post-Intralipid, FFA concentrations rose significantly and the FT4 changes agreed with the results of the in vitro experiments, except for the RG kit, for which FT4 increased in only nine patients. We conclude that in vitro oleate addition is useful to predict the in vivo effect of increased FFA on FT4 values; moreover, in serum from euthyroid subjects with high concentrations of FFA, FT4 analyzed with the CR or AA kits should better agree with normal results for thyrotropin than FT4 values measured with the other kits.
为比较游离脂肪酸（FFA）浓度升高对游离甲状腺素（FT4）值的体外和体内影响，我们在添加油酸的三种混合血清中以及在18名甲状腺功能正常的患者输注脂肪乳剂（英脱利匹特）前后的血清中测量了FT4。我们使用了五种FT4放射免疫分析试剂盒：两种两步法试剂盒[伽马包被，百特公司（GC）；放射免疫诊断试剂盒，贝林公司（RG）]，两种类似物放射免疫分析试剂盒[阿默莱克斯 - M，安玛西亚公司（AM）；科塔 - 瑞亚，生物梅里埃公司（CR）]，以及一种标记抗体试剂盒[阿默莱克斯 - MAB*，安玛西亚公司（AA）]。在体外，当油酸添加量最大达到5 mmol/L时，用GC和RG试剂盒测量时FT4升高，用AM试剂盒测量时FT4降低，而用CR和AA试剂盒测量时FT4无显著变化。在体内，输注英脱利匹特后，FFA浓度显著升高，FT4的变化与体外实验结果一致，但RG试剂盒除外，使用该试剂盒时只有9名患者的FT4升高。我们得出结论，体外添加油酸有助于预测FFA浓度升高对FT4值的体内影响；此外，在FFA浓度高的甲状腺功能正常受试者的血清中，用CR或AA试剂盒分析的FT4与促甲状腺激素的正常结果相比，应比用其他试剂盒测量的FT4值更相符。
