FETAL HEAT PRODUCTION AND TEMPERATURE REGULATION

胎儿产热和体温调节

• 批准号: 3313974
• 负责人: GORDON G POWER
• 金额: $ 18.69万
• 依托单位: LOMA LINDA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1982
• 资助国家: 美国
• 起止时间: 1982-07-01 至 1993-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3313974
• 关键词: bioenergetics; body temperature regulation; brown fat; calorimetry; embryo /fetus; gallamine triethiodide; heat stimulus; hypothermia; mathematical model; newborn animals; norepinephrine; oxygen consumption; placental transfer; propranolol; sheep; thermogenesis; thermometry; triiodothyronine

Shortly after birth the newborn's ability to produce additional heat may become critical for survival. The newborn lamb produces heat by shivering in skeletal muscle and nonshivering metabolic activity in brown fat. When cooled in utero, however, fetal thermogenic responses are relatively inactive. The purpose of these experiments is to investigate the factors which allow thermogenesis to become active at birth. We plan to examine the importance of rising levels of tri-iodothyronine (T3) and norepinephrine, the possibility of a placentally-synthetized inhibitor, the possibility of additional oxygen delivery to thermogenic organs by blood flow redistribution, the importance of kinetic factors, and a possible change in sensitivity of thermal receptors. These studies will use the chronically-prepared, unanesthetized fetal sheep. Birth will be simulated in utero by ventilating the lungs with oxygen and snaring the umbilical cord. Thermogenic responses to cooling will be monitored by measuring free fatty acids, glycerol, brown fat temperature, and whole-body oxygen consumption. The effects of exogenous hormones (T3 and beta-agonists), blockers (gallamine and propranolol), metabolic substrates, and cross-circulation between newborn and feta sheep, will be studied. This work relates to an understanding of temperature regulation and heat production in the fetal and newborn period and is thus relevant to clinical management at this time.

出生后不久，新生儿的能力，以产生额外的 热量可能成为生存的关键。 新生的羔羊 通过骨骼肌的颤抖产生热量， 棕色脂肪的代谢活动。 然而，当在子宫内冷却时， 胎儿产热反应相对不活跃。 目的 这些实验的目的是研究 产热在出生时就活跃起来。 我们计划检查 三碘甲状腺原氨酸（T3）水平升高的重要性， 去甲肾上腺素胎盘合成的 抑制剂，额外的氧气输送的可能性， 产热器官通过血流再分配， 动力学因素，以及热敏感性的可能变化， 受体。 这些研究将使用长期准备的， 未麻醉的胎羊。 出生将在子宫内模拟， 用氧气给肺部通气，然后勒住脐带 将通过测量来监测对冷却的产热反应。 游离脂肪酸、甘油、棕色脂肪温度和全身 耗氧量 外源激素（T3和 β-激动剂），阻滞剂（加拉明和普萘洛尔），代谢 基质，和新生儿和羊羊之间的交叉循环， 将被研究。 这项工作涉及到理解 胎儿的体温调节和产热， 新生儿期，因此与临床管理相关， 这次