Fetal sheep temperatures in utero during cooling and application of triiodothyronine, norepinephrine, propranolol and suxamethonium.
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Fetal sheep temperatures in utero during cooling and application of triiodothyronine, norepinephrine, propranolol and suxamethonium. / Schröder, H J; Hüneke, Bernd; Klug, A; Stegner, H; Carstensen, M; Leichtweiss, H P.
In: PFLUG ARCH EUR J PHY, Vol. 410, No. 4-5, 4-5, 1987, p. 376-384.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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T1 - Fetal sheep temperatures in utero during cooling and application of triiodothyronine, norepinephrine, propranolol and suxamethonium.
AU - Schröder, H J
AU - Hüneke, Bernd
AU - Klug, A
AU - Stegner, H
AU - Carstensen, M
AU - Leichtweiss, H P
PY - 1987
Y1 - 1987
N2 - Fetal sheep (n = 13) were chronically instrumented to measure temperatures in the maternal femoral artery (MAT), the amniotic fluid (AFT), the fetal brown adipose tissue (BFT) and the fetal arterial blood (DAT). Cooling loops were inserted into the amniotic cavity. In 4 fetuses osmotic minipumps delivering triiodothyronine (T3) were implanted subcutaneously. One to seven days after surgery the following results were obtained: 1) During control DAT was 0.59 +/- 0.2 degrees C (SD), BFT 0.60 +/- 0.24 degrees C and AFT 0.38 +/- 0.31 degrees C higher than MAT. T3 levels in treated fetuses were 3.4 +/- 1.5 micrograms/l. 2) Infusion of norepinephrine (NE) (5.2 +/- 0.9 micrograms/min per kg fetal body weight) with phentolamine (26.1 +/- 4.3 micrograms/min per kg) into a fetal vein did not change temperatures. 3) During cooling (-53 +/- 15 W) MAT decreased 0.45 +/- 0.3 degrees C, DAT 1.9 +/- 0.39 degrees C, BFT 1.61 +/- 0.52 degrees C and AFT 4.2 +/- 1.8 degrees C. 4) The amniotic fluid was cooled until steady state temperatures were achieved. Then propranolol (26.1 +/- 4.3 micrograms/min per kg) or suxamethonium (3 +/- 1 mg/kg) were introduced into the fetal vein. No consistent and significant changes of temperatures could be detected. It is concluded that 1) lowering the fetal core temperature by 1.6 - 1.9 degrees C and its ambient temperature (AFT) by 4.2 degrees C does not induce shivering or non-shivering thermogenesis suppressible by pharmacologic agents, 2) thermogenesis in fetal brown adipose tissue cannot be induced by NE (with or without supplemention of T3).(ABSTRACT TRUNCATED AT 250 WORDS)
AB - Fetal sheep (n = 13) were chronically instrumented to measure temperatures in the maternal femoral artery (MAT), the amniotic fluid (AFT), the fetal brown adipose tissue (BFT) and the fetal arterial blood (DAT). Cooling loops were inserted into the amniotic cavity. In 4 fetuses osmotic minipumps delivering triiodothyronine (T3) were implanted subcutaneously. One to seven days after surgery the following results were obtained: 1) During control DAT was 0.59 +/- 0.2 degrees C (SD), BFT 0.60 +/- 0.24 degrees C and AFT 0.38 +/- 0.31 degrees C higher than MAT. T3 levels in treated fetuses were 3.4 +/- 1.5 micrograms/l. 2) Infusion of norepinephrine (NE) (5.2 +/- 0.9 micrograms/min per kg fetal body weight) with phentolamine (26.1 +/- 4.3 micrograms/min per kg) into a fetal vein did not change temperatures. 3) During cooling (-53 +/- 15 W) MAT decreased 0.45 +/- 0.3 degrees C, DAT 1.9 +/- 0.39 degrees C, BFT 1.61 +/- 0.52 degrees C and AFT 4.2 +/- 1.8 degrees C. 4) The amniotic fluid was cooled until steady state temperatures were achieved. Then propranolol (26.1 +/- 4.3 micrograms/min per kg) or suxamethonium (3 +/- 1 mg/kg) were introduced into the fetal vein. No consistent and significant changes of temperatures could be detected. It is concluded that 1) lowering the fetal core temperature by 1.6 - 1.9 degrees C and its ambient temperature (AFT) by 4.2 degrees C does not induce shivering or non-shivering thermogenesis suppressible by pharmacologic agents, 2) thermogenesis in fetal brown adipose tissue cannot be induced by NE (with or without supplemention of T3).(ABSTRACT TRUNCATED AT 250 WORDS)
M3 - SCORING: Zeitschriftenaufsatz
VL - 410
SP - 376
EP - 384
JO - PFLUG ARCH EUR J PHY
JF - PFLUG ARCH EUR J PHY
SN - 0031-6768
IS - 4-5
M1 - 4-5
ER -