Effects of fasting and glucocorticoids on hepatic gluconeogenesis assessed using two independent methods in vivo
Effects of fasting and glucocorticoids on hepatic gluconeogenesis assessed using two independent methods in vivo
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DOI：
10.1152/ajpendo.00320.2002
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发表时间：
2002-11-01
影响因子：
5.1
通讯作者：
Cherrington, AD
中科院分区：
文献类型：
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作者：
Goldstein, RE;Rossetti, L;Cherrington, AD
本研究的目的是使用动静脉差异和[（14）C]磷酸烯醇化酶-肝活检技术以及两者的组合来比较过夜和长时间禁食状态下以及慢性高皮质醇血症期间的肝再生（GNG）评估。在研究前两周，将导管和流量探头植入狗的肝静脉、门静脉和股动脉。在禁食18小时（n = 8）、禁食42或66小时（n = 7）和禁食18小时加连续输注皮质醇（3.0 mug.kg（-1）.min（-1））72小时（n = 7）后对动物进行研究。每个实验由80分钟示踪剂（[ 3-（3）H]葡萄糖和[U-（14）C]丙氨酸）和染料平衡期（~ 80至0分钟）和45分钟采样期组成。在皮质醇治疗组，血浆皮质醇增加了五倍。在过夜禁食组中，总GNG通量速率（GNG（通量））、葡萄糖6-磷酸转化为葡萄糖（GNG（G-6-P-->Glc））、葡萄糖循环和最大GNG通量速率（GNG（max））分别为0.95 +/-0.14、0.65 +/-0.06、0.62 +/-0.06和0.70 +/-0.09 mg.kg（-1）.min（-1）.在长期禁食组中，它们分别为1.50 +/- 0.18、1.18 +/- 0.13、0.40 +/- 0.07和1.28 +/- 0.10 mg.kg（-1）.min（-1），而在皮质醇治疗组中，它们分别为1.64 +/- 0.33、0.99 +/- 0.29、1.32 +/- 0.24和0.91 +/- 0.13 mg.kg（-1）.min（-1）。这些结果表明GNG（G-6-P-->Glc）和GNG（max）几乎相同。然而，这些速率比通过两种方法的组合产生的GNG（通量）低15-38%。这种差异在类固醇治疗组中最为明显，其中两种方法的组合（GNG（通量））检测到致炎通量的显著增加。
The purpose of this study was to compare the assessment of gluconeogenesis (GNG) in the overnight- and prolonged-fasted states and during chronic hypercortisolemia using the arteriovenous difference and [(14)C] phosphoenolpyruvate-liver biopsy techniques as well as a combination of the two. Two weeks before a study, catheters and flow probes were implanted in the hepatic and portal veins and femoral artery of dogs. Animals were studied after an 18-h fast (n = 8), a 42- or 66-h fast (n = 7), and an 18-h fast plus a continuous infusion of cortisol (3.0 mug.kg(-1).min(-1)) for 72 h (n = 7). Each experiment consisted of an 80-min tracer ([ 3-(3)H] glucose and [U-(14)C] alanine) and dye equilibration period (-80 to 0 min) and a 45-min sampling period. In the cortisol-treated group, plasma cortisol increased fivefold. In the overnight- fasted group, total GNG flux rate (GNG(flux)), conversion of glucose 6-phosphate to glucose (GNG(G-6-P-->Glc)), glucose cycling, and maximal GNG flux rate (GNG(max)) were 0.95 +/- 0.14, 0.65 +/- 0.06, 0.62 +/- 0.06, and 0.70 +/- 0.09 mg.kg(-1).min(-1), respectively. In the prolonged-fasted group, they were 1.50 +/- 0.18, 1.18 +/- 0.13, 0.40 +/- 0.07, and 1.28 +/- 0.10 mg.kg(-1).min(-1), whereas in the cortisol-treated group they were 1.64 +/- 0.33, 0.99 +/- 0.29, 1.32 +/- 0.24, and 0.91 +/- 0.13 mg.kg(-1).min(-1). These results demonstrate that GNG(G-6-P-->Glc) and GNG(max) were almost identical. However, these rates were 15-38% lower than GNG(flux) generated by a combination of the two methods. This difference was most apparent in the steroid-treated group, where the combination of the two methods (GNG(flux)) detected a significant increase in gluconeogenic flux.