Maturation of endogenous glucose production in preterm and term calves.
Maturation of endogenous glucose production in preterm and term calves.
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早产和足月犊牛内源性葡萄糖产生的成熟。
DOI：
10.3168/jds.2011-4355
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发表时间：
2011
影响因子：
3.5
通讯作者：
H. Hammon
中科院分区：
文献类型：
--
作者：
J. Steinhoff;S. Görs;P. Junghans;R. Bruckmaier;E. Kanitz;C. Metges;H. Hammon
新生犊牛的葡萄糖代谢能力常常受到损害，早产犊牛的血糖消耗能力更严重。本研究的目的是调查犊牛内源性葡萄糖产生（eGP）的个体成熟及其对产后葡萄糖稳态的影响。犊牛（每组 n = 7 头）为早产（PT；足月前 9 天分娩）或足月出生（T；自然阴道分娩），或自然出生并饲喂初乳 4 天（TC）。出生后立即、喂养前和喂养后 2 小时、出生后 24 小时 (PT; T) 或生后第 4 天 (TC) 采集血样，以确定代谢和内分泌变化。出生后（PT 和 T）或生后第 3 天（TC），禁食的小牛用氘标记的水灌胃以确定糖异生（GNG），并静脉输注 [U(13)C]-葡萄糖以测量血浆中的 eGP 和葡萄糖氧化（GOx）。屠宰后，在出生后26小时（PT、T）或生后第4天（TC），测量肝脏中的糖原浓度和肝脏mRNA浓度以及丙酮酸羧化酶、磷酸烯醇丙酮酸羧激酶（PEPCK）和葡萄糖-6-磷酸酶的酶活性。早产犊牛出生时血浆皮质醇和 3,5,3'-三碘甲状腺原氨酸浓度最低。第 1 天至第 2 天的血浆葡萄糖浓度下降更多，但 PT 犊牛的血浆乳酸和尿素浓度以及胰高血糖素：胰岛素比值高于 T 和 TC 犊牛。 PT 小牛的 eGP、GNG、GOx 以及肝糖原浓度和 PEPCK 活性最低。结果表明，由于 PT 小牛 eGP 减少以及 eGP 随着个体发育而成熟，葡萄糖稳态受损。
Glucose disposability is often impaired in neonatal calves and even more in preterm calves. The objective of this study was to investigate ontogenic maturation of endogenous glucose production (eGP) in calves and its effects on postnatal glucose homeostasis. Calves (n = 7 per group) were born preterm (PT; delivered by section 9 d before term) or at term (T; spontaneous vaginal delivery), or spontaneously born and fed colostrum for 4 d (TC). Blood samples were taken immediately after birth and before and 2h after feeding at 24h after birth (PT; T) or on d 4 of life (TC) to determine metabolic and endocrine changes. After birth (PT and T) or on d 3 of life (TC), fasted calves were gavaged with deuterium-labeled water to determine gluconeogenesis (GNG) and intravenously infused with [U(13)C]-glucose to measure eGP and glucose oxidation (GOx) in blood plasma. After slaughter at 26h after birth (PT, T) or on d 4 of life (TC), glycogen concentrations in liver and hepatic mRNA concentrations and enzyme activities of pyruvate carboxylase, phosphoenolpyruvate carboxykinase (PEPCK), and glucose-6-phosphatase were measured. Preterm calves had the lowest plasma concentrations of cortisol and 3,5,3'-triiodothyronine at birth. Plasma glucose concentrations from d 1 to 2 decreased more, but plasma concentrations of lactate and urea and glucagon:insulin ratio were higher in PT than in T and TC calves. The eGP, GNG, GOx, as well as hepatic glycogen concentrations and PEPCK activities, were lowest in PT calves. Results indicate impaired glucose homeostasis due to decreased eGP in PT calves and maturation of eGP with ontogenic development.