The effects of acute elevations in plasma cortisol levels on alanine metabolism in the conscious dog.
The effects of acute elevations in plasma cortisol levels on alanine metabolism in the conscious dog.
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血浆皮质醇水平急剧升高对清醒狗丙氨酸代谢的影响。
DOI：
10.1016/0026-0495(92)90099-v
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Cherrington,AD
中科院分区：
文献类型：
--
作者：
Goldstein,RE;Reed,GW;Wasserman,DH;Williams,PE;Lacy,DB;Buckspan,R;Abumrad,NN;Cherrington,AD
本研究是为了确定是否急性生理性增加血浆皮质醇水平有显着影响丙氨酸代谢和代谢3小时内清醒，过夜禁食狗。每个实验包括80分钟的示踪剂和染料平衡期、40分钟的基础期和3小时的实验期。在平衡期开始时开始[3- 3 H]葡萄糖的预充、连续输注以及[U-14 C]丙氨酸和吲哚菁绿色染料的连续输注，并在整个实验中继续。对狗进行了以下研究：（1）氢化可的松输注（[CORT] 3.0 μg · kg-1· min-1，n = 5），（2）氢化可的松输注与CORT相同，但使用生长抑素和基础门静脉内胰岛素和胰高血糖素替代品（CLAMP + CORT，n = 5）钳夹胰腺激素，或（3）在胰腺钳夹期间输注盐水（CLAMP，n = 5）。葡萄糖生成和血管生成用示踪剂和动静脉差分技术测定。在CLAMP过程中，除了丙氨酸向葡萄糖的致热转化率适度增加67% ± 6%和致热效率增加53% ± 26%之外，所有参数均稳定。当CLAMP + CORT期间血浆皮质醇水平增加4倍时，葡萄糖的浓度、产生或清除没有变化。丙氨酸转化为葡萄糖的葡萄糖异生转化率增加了10% ± 34%，异生效率增加了65% ± 43%，而肝丙氨酸净摄取（NHAU）增加了60% ± 19%，肝丙氨酸提取率增加了38% ± 12%。皮质醇没有引起动脉甘油水平或肝甘油净摄取的增加。当血浆皮质醇水平增加，胰腺激素被允许改变（CORT），有一个短暂的，但显着降低血浆胰岛素水平，而血浆胰高血糖素水平保持不变。葡萄糖浓度、产量（Ra）或清除率无变化。然而，丙氨酸的异构转化率增加了190% ± 59%，异构效率增加了57% ± 43%，NHAO增加了75% ± 25%，肝丙氨酸分数提取增加了48% ± 6%。在氢化可的松输注的前90分钟，这些变化均具有统计学显著性。此外，与其他两组相比，肝脏乳酸净生成量和肝脏甘油净摄取量均有升高的趋势。这些结果表明，血浆皮质醇水平的急性生理性增加可以通过增加NHAU和丙氨酸的肝脏分数提取来增加丙氨酸向葡萄糖的致炎性转化。这种血浆皮质醇水平的增加也可能与血浆胰岛素水平的短暂降低有关，这可能进一步促进胰岛素生成。
The present study was undertaken to determine whether an acute physiological increase in plasma cortisol level had significant effects on alanine metabolism and gluconeogenesis within 3 hours in conscious, overnight-fasted dogs. Each experiment consisted of an 80-minute tracer and dye equilibration period, a 40-minute basal period, and a 3-hour experimental period. A primed, continuous infusion of [3-3H]glucose and continuous infusions of [U-14C]alanine and indocyanine green dye were initiated at the start of the equilibration period and continued throughout the experiment. Dogs were studied with (1) a hydrocortisone infusion ([CORT] 3.0 μg · kg−1· min−1, n = 5), (2) hydrocortisone infused as in CORT, but with pancreatic hormones clamped using somatostatin and basal intraportal replacement of insulin and glucagon (CLAMP + CORT, n = 5), or (3) saline infusion during a pancreatic clamp (CLAMP, n = 5). Glucose production and gluconeogenesis were determined using tracer and arteriovenous difference techniques. During CLAMP, all parameters were stable except for a modest 67% ± 6% increase in gluconeogenic conversion of alanine to glucose and a 53% ± 26% increase in gluconeogenic efficiency. When plasma cortisol levels were increased fourfold during CLAMP + CORT, there was no change in the concentration, production, or clearance of glucose. Gluconeogenic conversion of alanine to glucose increased 10% ± 34% and gluconeogenic efficiency increased 65% ± 43%, while net hepatic alanine uptake (NHAU) increased 60% ± 19% and hepatic fractional extraction of alanine increased 38% ± 12%. Cortisol did not cause an increase in the arterial glycerol level or net hepatic glycerol uptake. When plasma cortisol levels were increased and the pancreatic hormones were allowed to change (CORT), there was a transient but significant decrease in plasma insulin levels, while plasma glucagon levels remained unchanged. There was no change in the concentration, production (Ra), or clearance of glucose. However, gluconeogenic conversion of alanine increased 190% ± 59%, gluconeogenic efficiency increased 57% ± 43%, NHAO increased 75% ± 25%, and hepatic alanine fractional extraction increased 48% ± 6%. These changes were all statistically significant by the first 90 minutes of hydrocortisone infusion. In addition, there was a tendency for both net hepatic production of lactate and net hepatic uptake of glycerol to be elevated compared with the other two groups. These results suggest that an acute physiologic increase in plasma cortisol level can increase the gluconeogenic conversion of alanine to glucose by increasing both NHAU and hepatic fractional extraction of alanine. This increase in plasma cortisol level may also be associated with a transient decrease in plasma insulin level that may further promote gluconeogenesis.
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胰岛素对清醒狗胰高血糖素刺激的葡萄糖产生的影响。
DOI：
10.1016/0026-0495(90)90192-f
发表时间：
1990
期刊：
Metabolism: clinical and experimental
影响因子：
--
作者：
K. Steiner;P. Williams;W. Lacy;A. Cherrington
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影响因子：
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DOI：
--
发表时间：
1975
期刊：
Metabolism: Clinical and Experimental
影响因子：
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影响因子：
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DOI：
10.1152/ajpendo.1990.258.4.e569
发表时间：
1990
期刊：
The American journal of physiology
影响因子：
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