Iqbal A, Cheema A M, Kühn E R
Laboratory of Comparative Endocrinology, Zoological Institute, K.U.L., Leuven, Belgium.
Horm Metab Res. 1990 Nov;22(11):566-8. doi: 10.1055/s-2007-1004974.
Fed and food deprived (7 days) adult dwarf goats were injected intravenously with 75 micrograms/kg b. w. of ovine growth hormone (o-GH). Blood samples were collected from the jugular vein -2, -1 and 0 hr prior to and 30, 60, 90 and 120 min after injection and assayed for thyroxine (T4) and triiodothyronine (T3) concentrations. The 5'-monodeiodination (5'-D) activity was consequently determined in liver and kidney samples following slaughtering. Fasting alone increased plasma concentrations of T3 and T4, whereas injection of o-GH raised T3 additionally and more profoundly in food deprived animals compared to fed ones. A small increase in plasma T4 was also observed following o-GH injection, but only in starved goats. At the same time the hepatic, but not the kidney, 5'-D activity was stimulated in food deprived and GH injected animals. It is concluded that during prolonged fasting an increased peripheral T4 to T3 conversion is occurring contrary to the known decrease in T3 production during short periods of food deprivation. This increased conversion may be under the control of GH.
对处于喂食状态和禁食7天的成年矮山羊静脉注射每千克体重75微克的绵羊生长激素（o-GH）。在注射前2小时、1小时和0小时以及注射后30分钟、60分钟、90分钟和120分钟从颈静脉采集血样，测定甲状腺素（T4）和三碘甲状腺原氨酸（T3）浓度。屠宰后，随后测定肝脏和肾脏样本中的5'-单脱碘酶（5'-D）活性。单独禁食会增加血浆T3和T4浓度，而与喂食的动物相比，注射o-GH会使禁食动物的T3进一步且更显著地升高。注射o-GH后也观察到血浆T4略有增加，但仅在饥饿的山羊中出现。同时，在禁食且注射生长激素的动物中，肝脏而非肾脏的5'-D活性受到刺激。得出的结论是，在长期禁食期间，外周T4向T3的转化率增加，这与已知的短期食物剥夺期间T3生成减少相反。这种增加的转化率可能受生长激素的控制。
