Liberman U A, Asano Y, Lo C S, Edelman I S
Biophys J. 1979 Jul;27(1):127-44. doi: 10.1016/S0006-3495(79)85207-8.
Administration of three successive doses of triiodothyronine (T3) (50 micrograms/100 g body wt), given on alternate days to thyroidectomized and euthyroid rats, stimulated oxygen consumption (QO2) and Na+ transport-dependent respiration (QO2 [5]) in the stripped jejunal mucosa, a preparation that consisted mostly of epithelial cells. The increase in QO2(t) accounted for 57% of the increment in QO2 in the transition from the hypothyroid to the euthyroid state and for 29% of the increment in the transition from the euthyroid to the hyperthyroid state. Administration of T3 to hypothyroid rats also increased the yield of epithelial cells. Injection of T3 into thyroidectomized and euthyroid rats increased the specific activity (at Vmax) of the (Na+ + K+)-dependent adenosine triphosphatase (NaK-ATPase) in jejunal crude membrane preparations. No significant change was recorded in the activity of Mg-ATPase in the same preparation. The ratio of QO2/NaK-ATPase and QO2(t)/NaK-ATPase in the various thyroid states remained constant, indicating proportionate increased in the respiratory and enzymatic indices. The effect of administration of T3 to thyroidectomized rats on the number of NaK-ATPase units (recovered in the crude membrane preparation) was estimated by: (a) Na+ + Mg++ + ATP-dependent binding of [3H]-ouabain to crude membrane fractions, and (b) the amount of the phosphorylated intermediate formed in the NaK-ATPase reaction from AT32P(gamma). Estimates were obtained of the maximal number of [3H]ouabain binding sites (Nm) and dissociation constants (Kd). Nm for [3H]ouabain and Nak-ATPase specific activity increased to about the same extent after T3 administration to thyroidectomized rats, with no change in the apparent Kd values. The amount of phosphorylated intermediate formed in jejunal crude membrane preparations also increased significantly. Thus, thyroid hormone administration may increase the number of active Na+pump sites in the plasma membrane. The apparent increase in the number of Na+ pump sites also correlated with the hormone dependent increases in QO2 and QO2(t).
对甲状腺切除和甲状腺功能正常的大鼠隔日给予连续三剂三碘甲状腺原氨酸（T3）（50微克/100克体重），可刺激剥离的空肠黏膜（一种主要由上皮细胞组成的标本）中的氧消耗（QO2）和钠转运依赖性呼吸（QO2[5]）。QO2(t)的增加在从甲状腺功能减退状态转变为甲状腺功能正常状态时占QO2增量的57%，在从甲状腺功能正常状态转变为甲状腺功能亢进状态时占增量的29%。对甲状腺功能减退的大鼠给予T3也增加了上皮细胞的产量。向甲状腺切除和甲状腺功能正常的大鼠注射T3可增加空肠粗膜制剂中（钠+钾）依赖性腺苷三磷酸酶（NaK-ATPase）的比活性（在Vmax时）。在相同制剂中，Mg-ATPase的活性未记录到显著变化。不同甲状腺状态下QO2/NaK-ATPase和QO2(t)/NaK-ATPase的比值保持恒定，表明呼吸和酶指标成比例增加。通过以下方法评估对甲状腺切除大鼠给予T3对NaK-ATPase单位数量（在粗膜制剂中回收）的影响：（a）[3H]哇巴因与粗膜部分的钠+镁+++ATP依赖性结合，以及（b）在NaK-ATPase反应中由AT32P（γ）形成的磷酸化中间体的量。获得了[3H]哇巴因结合位点的最大数量（Nm）和解离常数（Kd）的估计值。对甲状腺切除大鼠给予T3后，[3H]哇巴因的Nm和Nak-ATPase比活性增加到大致相同的程度，表观Kd值没有变化。空肠粗膜制剂中形成的磷酸化中间体的量也显著增加。因此，给予甲状腺激素可能会增加质膜中活性钠泵位点的数量。钠泵位点数量的明显增加也与激素依赖性的QO2和QO2(t)增加相关。
