EFFECTS OF THYROID-HORMONES ON THYMOCYTE ENERGETICS

It has been demonstrated that on administration of thyroxine (T4) for 7 days at 200 mug per kg of mass, pyruvate being the substrate of oxid ation, the rate of oxygen consumption increases by 46% alongside with uncoupling of oxidative phosphorylation (OP), as evidenced by the incr eased rate of respiration with oligomycin. mycin. Preincubation of thy mocytes with triidothyronine (T3) (1 muM) for 15 min stimulates oxidat ion of pyruvate by 42% without any uncoupling of OP. Thyroidectomy bri ngs about a decrease in the rate of respiration of thycomytes by 44% a s related to the cells of falsely thyroidectomyzed animals without unc oupling of OP. Tehrefore, the energy metabolism of thymocytes is regul ated by thyroid hormones the same way as hepatocyte metabolism.