Macari M, Dauncey M J, Ramsden D B, Ingram D L
Q J Exp Physiol. 1983 Oct;68(4):709-18. doi: 10.1113/expphysiol.1983.sp002760.
The separate effects of ambient temperature and energy intake on the metabolism of thyroid hormones in the young pig have been investigated. Piglets were kept singly from 4 weeks of age at 10 or 35 degrees C on a high (H), or low (L) energy intake, such that H = 2L. At the tenth week of age blood samples were taken 16-21 h after the last meal for the determination of plasma concentrations of thyroxine (T4) and 3,5,3'-triiodothyronine (T3). At the end of the tenth week of age the fractional disappearance rate (K) of T4 was determined and finally the K value for T3 was estimated. Plasma concentrations of T4 and T3 were greater in animals on a high intake than in those on a low intake, (P less than 0.02), but the temperature at which the animals lived had no significant effect. The values of K for T4 and T3 were greater at 10 than at 35 degrees C (P less than 0.010 and P less than 0.05), and energy intake had no significant effect. Calculations of the catabolic rates in nmol/kg X h revealed that for T4 the rate was greater at 10 than at 35 degrees C (P less than 0.001) and on a high than on a low intake (P less than 0.01). Similar differences were found between the mean values of T3 with respect to both temperature and energy intake, but the variance was large and they did not reach statistical significance. It is concluded that the metabolism of thyroid hormones is influenced independently by both ambient temperature and energy intake.
研究了环境温度和能量摄入对幼猪甲状腺激素代谢的单独影响。仔猪从4周龄开始单独饲养，分别处于10℃或35℃的环境中，能量摄入分为高（H）、低（L）两种水平，且H = 2L。在10周龄时，于最后一次进食16 - 21小时后采集血样，以测定血浆甲状腺素（T4）和3,5,3'-三碘甲状腺原氨酸（T3）的浓度。在10周龄末，测定T4的分数消失率（K），最后估算T3的K值。高能量摄入组动物的血浆T4和T3浓度高于低能量摄入组（P < 0.02），但动物所处环境温度无显著影响。T4和T3的K值在10℃时高于35℃（P < 0.010和P < 0.05），能量摄入无显著影响。以nmol/kg×h为单位计算分解代谢率表明，T4的分解代谢率在10℃时高于35℃（P < 0.001），且高能量摄入组高于低能量摄入组（P < 0.01）。在T3的平均值方面，温度和能量摄入也存在类似差异，但方差较大，未达到统计学显著性。研究得出结论，甲状腺激素的代谢分别受环境温度和能量摄入的独立影响。
