Zemel L R, Biezunski D R, Shapiro L E, Surks M I
Department of Medicine, Montefiore Medical Center, Bronx.
Acta Endocrinol (Copenh). 1988 Mar;117(3):392-8. doi: 10.1530/acta.0.1170392.
We determined the effect of 5,5'-diphenylhydantoin (DPH) on the kinetics of T3 and T4 uptake in cultured GH-producing (GC) cells under serum-free conditions. GC cells accumulated [125I]T3 at a greater fractional rate than [125I]T4. The t 1/2 of exit of [125I]T4 and [125I]T3 previously equilibrated in GC cells was 28 min for T4 and 66 min for T3. T3 and T4 entry rates were not influenced by up to a 10,000-fold molar excess of nonradioactive T3, T4, d-T4, rT3, 3,5-T2 and diiodotyrosine. Thus, entry of T3 and T4 in GC cells appeared nonsaturable and was not influenced by various thyroid hormone analogues. DPH, 25-200 mumol/l, decreased the rate of T3 entry in a dose-dependent manner and did not influence the T3 exit rate. At 200 mumol/l DPH, T3 entry decreased by 40%. Rates of entry and exit of T4 were unaffected by DPH. DPH may affect T3 and T4 entry differentially at the level of the plasma membrane.
我们在无血清条件下，测定了5,5'-二苯基乙内酰脲（DPH）对培养的生长激素分泌（GC）细胞摄取T3和T4动力学的影响。GC细胞以比[125I]T4更高的分数速率积累[125I]T3。先前在GC细胞中达到平衡的[125I]T4和[125I]T3的排出半衰期，T4为28分钟，T3为66分钟。T3和T4的进入速率不受高达10000倍摩尔过量的非放射性T3、T4、d-T4、rT3、3,5-T2和二碘酪氨酸的影响。因此，T3和T4进入GC细胞似乎是非饱和的，并且不受各种甲状腺激素类似物的影响。25 - 200μmol/L的DPH以剂量依赖的方式降低T3的进入速率，并且不影响T3的排出速率。在200μmol/L DPH时，T3的进入减少了40%。T4的进入和排出速率不受DPH的影响。DPH可能在质膜水平上对T3和T4的进入产生不同的影响。
