FETAL HEAT PRODUCTION AND TEMPERATURE REGULATION

胎儿产热和体温调节

• 批准号: 3313977
• 负责人: GORDON G POWER
• 金额: $ 18.42万
• 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/3313977
• 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，新生儿的能力产生额外的