Ismail-Beigi F, Bissell D M, Edelman I S
J Gen Physiol. 1979 Mar;73(3):369-83. doi: 10.1085/jgp.73.3.369.
We have studied the effect of 3,5,3'-triiodothyronine (T3) on the respiration of adult rat hepatocytes in primary monolayer culture prepared from hypothyroid rat liver. After addition of T3 to the culture medium at a concentration of 2 x 10(-7) M, oxygen consumption of the cultured cells increased detectably at 24 h and was maximal at 72--96 h, relative to control cultures (38.0 +/- 1.8 vs. 25.0 +/- 1.5 microliter/h.mg protein). The thyroid-responsive enzymes, Na+ + K+-activated adenosine triphosphatase (NaK-ATPase) and alpha-glycerophosphate dehydrogenase (GPD), each exhibited increased activity in response to T3, in parallel with the change in oxygen consumption, whereas the activity of Mg-dependent ATPase was unaffected. These responses to T3 were dose dependent over similar concentration ranges, the half-maximal response for each occurring at ca 8 x 10(-10) M. In thyroid-treated cells, the observed increase in respiration was almost completely (90%) inhibited after addition of ouabain (10(-3) M) to the culture medium. It was found also that a 4-h exposure of the cultured hepatocytes to T3 was sufficient to elicit a significant thermogenic response, measured at a time (48 h later) when T3 was no longer present in the medium. The response to T3 occurred in fully defined culture medium and was independent of the presence or absence of hypothyroid rat serum, corticosterone, or insulin, and cellular ATP was unaffected by T3 in concentrations up to 2 x 10(-7) M. The findings document that adult rat hepatocytes in primary monolayer culture respond directly to thyroid hormone; the increases in respiration and NaK-ATPase activity elicited by T3 were cotemporal and apparently coordinate.
我们研究了3,5,3'-三碘甲腺原氨酸（T3）对由甲状腺功能减退大鼠肝脏制备的原代单层培养成年大鼠肝细胞呼吸作用的影响。在培养基中添加浓度为2×10⁻⁷ M的T3后，培养细胞的耗氧量在24小时时可检测到增加，并在72 - 96小时达到最大值，相对于对照培养物（38.0±1.8对25.0±1.5微升/小时·毫克蛋白）。甲状腺反应性酶，即钠钾激活的三磷酸腺苷酶（NaK - ATPase）和α - 甘油磷酸脱氢酶（GPD），各自对T3的反应均表现出活性增加，与耗氧量的变化平行，而镁依赖性ATP酶的活性未受影响。在相似浓度范围内，这些对T3的反应呈剂量依赖性，每种反应的半数最大反应发生在约8×10⁻¹⁰ M。在甲状腺处理的细胞中，向培养基中添加哇巴因（10⁻³ M）后，观察到的呼吸增加几乎完全（90%）受到抑制。还发现培养的肝细胞暴露于T3 4小时足以引发显著的产热反应，该反应在培养基中不再存在T3时（48小时后）测量。对T3的反应发生在完全确定的培养基中，并且与甲状腺功能减退大鼠血清、皮质酮或胰岛素的存在与否无关，细胞ATP在浓度高达2×10⁻⁷ M时不受T3影响。这些发现证明原代单层培养的成年大鼠肝细胞直接对甲状腺激素作出反应；T3引起的呼吸和NaK - ATPase活性增加是同时发生的，并且明显是协调的。
