Lactate flux and gluconeogenesis in fasting, weaned northern elephant seals (Mirounga angustirostris)
Lactate flux and gluconeogenesis in fasting, weaned northern elephant seals (Mirounga angustirostris)
复制标题
禁食、断奶的北象海豹（Mirounga angustirostris）的乳酸通量和糖异生
DOI：
--
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
D. Crocker
中科院分区：
文献类型：
--
作者：
S. Tavoni;C. Champagne;D. Houser;D. Crocker
象海豹保持内源性葡萄糖产生（EGP）的吸收后的哺乳动物的典型率，尽管持久的长期食物匮乏，同时低速率的葡萄糖氧化。这些高EGP率表明禁食期间广泛的葡萄糖再循环。我们研究了禁食海象的乳酸代谢，以评估其在葡萄糖再循环中的作用。使用[U-14 C]乳酸盐和[6- 3 H]葡萄糖的预充恒定输注，以葡萄糖和乳酸盐（分别为Ragluc和Ralac）的出现率测量全动物葡萄糖和乳酸盐通量，并计算乳酸盐对胚胎发生的最小贡献（GNGlac）。与其他物种的静息值相比，Ralac较高（3.21 ± 0.71 mmol min−1* kg−1），在禁食14 ± 1天和31 ± 8天之间没有变化，并且与Raglu直接相关。最小GNGlac为EGP的44.6 ± 6.0%，直接随血浆乳酸水平变化，且在禁食期间不变化。Ralac和Raglu均与血浆胰岛素浓度直接相关。这些数据表明，乳酸盐是主要的促血管生成的前体在禁食的海象和高速率的葡萄糖再循环通过科里循环活动有助于维持EGP在禁食期间。高水平的科里循环活性和EGP可能是代谢适应的重要组成部分，在延长禁食期间维持葡萄糖产生，同时避免酮症，或者与象海豹中与延长屏气相关的持续代谢改变有关。
Elephant seals maintain rates of endogenous glucose production (EGP) typical of post-absorptive mammals despite enduring prolonged periods of food deprivation concurrent with low rates of glucose oxidation. These high rates of EGP suggest extensive glucose recycling during fasting. We investigated lactate metabolism in fasting elephant seals to assess its role in glucose recycling. Whole-animal glucose and lactate fluxes were measured as the rates of appearance of glucose and lactate (Ragluc and Ralac, respectively) using a primed constant infusion of [U-14C] lactate and [6-3H] glucose, and we calculated the minimum contribution of lactate to gluconeogenesis (GNGlac). Ralac was high compared to resting values in other species (3.21 ± 0.71 mmol min−1* kg−1), did not change between 14 ± 1 and 31 ± 8 days of fasting and varied directly with Raglu. The minimum GNGlac was 44.6 ± 6.0 % of EGP, varied directly with plasma lactate levels, and did not change over the fast. Ralac and Raglu both varied directly with plasma insulin concentrations. These data suggest that lactate is the predominant gluconeogenic precursor in fasting elephant seals and that high rates of glucose recycling through Cori cycle activity contribute to the maintenance of EGP during fasting. High levels of Cori cycle activity and EGP may be important components of metabolic adaptations that maintain glucose production while avoiding ketosis during extended fasting or are related to sustained metabolic alterations associated with extended breath-holds in elephant seals.
登录
查看更多内容
影响因子：
10.5
作者：
Iyer, NV;Kotch, LE;Semenza, GL
通讯作者：
Semenza, GL
影响因子：
15.9
作者：
CONSOLI, A;KENNEDY, F;GERICH, J
通讯作者：
GERICH, J
葡萄糖摄入后乳酸的产生：与肥胖、碳水化合物耐受性和胰岛素敏感性的关系。
影响因子：
4.9
作者：
Lovejoy,J;Mellen,B;Digirolamo,M
通讯作者：
Digirolamo,M
DOI：
10.1210/jcem.84.1.5377
发表时间：
1999
期刊：
The Journal of clinical endocrinology and metabolism.
影响因子：
--
作者：
Feneberg,R;Sparber,M;Veldhuis,JD;Mehls,O;Ritz,E;Schaefer,F
通讯作者：
Schaefer,F
DOI：
10.1152/ajpendo.1998.275.3.e537
发表时间：
1998-09-01
影响因子：
5.1
作者：
Katz, J;Tayek, JA
通讯作者：
Tayek, JA