Simonetta G, Young I R, McMillen I C
Department of Physiology, Monash University, Clayton, Victoria, Australia.
J Neurochem. 1994 Oct;63(4):1386-91. doi: 10.1046/j.1471-4159.1994.63041386.x.
We have investigated the effects of fetal hypophysectomy (HX) with or without thyroxine (T4)replacement on the plasma concentrations of free methionine-enkephalin (free Met-Enk), noradrenaline, and adrenaline in late gestation sheep fetus. Plasma adrenaline concentrations were significantly higher in intact fetal sheep (1.05 +/- 0.12 pmol/L) between 125 and 140 days of gestation when compared with the HX + saline (0.64 +/- 0.10 pmol/L) and HX + T4 (0.61 +/- 0.08 pmol/L) groups. During the first 15 days of the T4 or saline infusion, the plasma concentrations of free Met-Enk were significantly higher in the HX + T4 group (392 +/- 40 pmol/L) than in the HX + saline group (299 +/- 43 pmol/L). At this stage of gestation, however, circulating concentrations of free Met-Enk were significantly higher in intact fetal sheep (556 +/- 51 pmol/L) than in either of the HX groups. Between 125 and 140 days of gestation, plasma free Met-Enk concentrations were similar and significantly higher in the intact and HX + T4 groups than those measured in the HX + saline fetal sheep. We conclude that the decrease in circulating free Met-Enk concentrations after removal of the fetal pituitary is primarily a consequence of functional athyroidism.
我们研究了胎羊垂体切除（HX）且有或无甲状腺素（T4）替代治疗对妊娠晚期胎羊血浆中游离蛋氨酸脑啡肽（游离Met-Enk）、去甲肾上腺素和肾上腺素浓度的影响。与垂体切除+生理盐水组（0.64±0.10 pmol/L）和垂体切除+T4组（0.61±0.08 pmol/L）相比，妊娠125至140天完整胎羊的血浆肾上腺素浓度显著更高（1.05±0.12 pmol/L）。在输注T4或生理盐水的前15天，垂体切除+T4组（392±40 pmol/L）的血浆游离Met-Enk浓度显著高于垂体切除+生理盐水组（299±43 pmol/L）。然而，在此妊娠阶段，完整胎羊的游离Met-Enk循环浓度（556±51 pmol/L）显著高于任何一组垂体切除组。在妊娠125至140天期间，完整组和垂体切除+T4组的血浆游离Met-Enk浓度相似，且显著高于垂体切除+生理盐水组的胎羊。我们得出结论，去除胎儿垂体后循环中游离Met-Enk浓度的降低主要是功能性甲状腺功能减退的结果。
