Heasman L, Clarke L, Symonds M E
Academic Division of Child Health, University Hospital, Queen's Medical Centre, Nottingham, United Kingdom.
Am J Obstet Gynecol. 2000 Nov;183(5):1257-62. doi: 10.1067/mob.2000.106714.
We examined the hypothesis that exogenous stimulation with thyrotropin-releasing hormone immediately before umbilical cord clamping can improve thermoregulation in near-term lambs delivered by cesarean.
Twin lambs were injected with either saline solution alone (control, n = 12) or thyrotropin-releasing hormone in saline solution (n = 16) and were immediately placed in a warm (30 degrees C; n = 14) or cool (15 degrees C; n = 14) ambient temperature. In vivo measurements of temperature control (colonic temperature, oxygen consumption, and incidence of shivering) were then performed during the first 6 hours after birth, in conjunction with plasma thyroid hormone measurements. Brown adipose tissue was then sampled for measurement of uncoupling protein 1 abundance.
Plasma triiodothyronine concentrations were significantly higher in lambs treated with thyrotropin-releasing hormone than in control lambs between 3 and 6 hours after birth, as were plasma thyroxine concentrations 1 and 5 hours after birth. Delivery temperature had no effect on plasma thyroid hormone concentrations. At 6 hours after birth the abundance of uncoupling protein 1 was higher in lambs treated with thyrotropin-releasing hormone than in control lambs. Lambs treated with thyrotropin-releasing hormone exhibited a lower incidence of shivering than did control lambs between 5 and 6 hours after birth, and an effect of ambient temperature on the incidence of shivering was observed only in the control group. From 3 to 6 hours after birth colonic temperature was significantly higher in cool-delivered lambs treated with thyrotropin-releasing hormone than in the control group. Oxygen consumption was higher in cool-delivered lambs than warm-delivered lambs, but this was not influenced by thyrotropin-releasing hormone. Irrespective of delivery temperature, lambs treated with thyrotropin-releasing hormone possessed more pericardial adipose tissue and hepatic glycogen than did control lambs.
Thyrotropin-releasing hormone treatment stimulated thyroid hormone secretion in the neonatal lamb and improved thermoregulation during the first 6 hours after birth in near-term lambs delivered by cesarean under cool conditions.
我们检验了这样一种假设，即在脐带夹闭前立即用促甲状腺激素释放激素进行外源性刺激，可以改善剖宫产娩出的近足月羔羊的体温调节。
将双胎羔羊分别注射生理盐水（对照组，n = 12）或生理盐水加促甲状腺激素释放激素（n = 16），并立即置于温暖（30℃；n = 14）或凉爽（15℃；n = 14）的环境温度中。然后在出生后的前6小时内进行体温控制的体内测量（结肠温度、耗氧量和颤抖发生率），同时测量血浆甲状腺激素。随后采集棕色脂肪组织样本以测量解偶联蛋白1的丰度。
出生后3至6小时，用促甲状腺激素释放激素治疗的羔羊血浆三碘甲状腺原氨酸浓度显著高于对照组羔羊，出生后1小时和第5小时血浆甲状腺素浓度也是如此。分娩时的温度对血浆甲状腺激素浓度没有影响。出生后6小时，用促甲状腺激素释放激素治疗的羔羊解偶联蛋白1的丰度高于对照组羔羊。出生后5至6小时，用促甲状腺激素释放激素治疗的羔羊颤抖发生率低于对照组羔羊，且仅在对照组中观察到环境温度对颤抖发生率的影响。出生后3至6小时，凉爽环境下分娩且用促甲状腺激素释放激素治疗的羔羊结肠温度显著高于对照组。凉爽环境下分娩的羔羊耗氧量高于温暖环境下分娩的羔羊，但这不受促甲状腺激素释放激素的影响。无论分娩时的温度如何，用促甲状腺激素释放激素治疗的羔羊心包脂肪组织和肝糖原均多于对照组羔羊。
促甲状腺激素释放激素治疗刺激了新生羔羊的甲状腺激素分泌，并改善了剖宫产娩出的近足月羔羊在凉爽条件下出生后前6小时的体温调节。
