Lumholtz I B, Siersbaek-Nielsen K, Faber J, Kirkegaard C, Friis T
J Clin Endocrinol Metab. 1978 Sep;47(3):587-9. doi: 10.1210/jcem-47-3-587.
Kinetic studies of T4 and T3 using a noncompartmental approach were performed in seven patients with pretreatment severe hypothyroidism maintained on L-T4 replacement. Each subject received a combined tracer dose of labeled T4 and T3 as an iv bolus before and during peroral treatment with propranolol. Serum T4 was unchanged, while a significant decrease of 13% was found in serum T3. The disposal rates (DR) of T4 and T3 decreased significantly, and the ratio between the DR off T3 and the DR of T4, the conversion rate, was significantly reduced during propranolol treatment. The decrease in the DR of T4 suggests a reduction in the bioavailability of L-T4 during propranolol, possibly due to a decrease in intestinal absorption. The decrease in the conversion rate indicates a reduced extrathyroidal conversion of T4 to T3 during propranolol treatment.
采用非房室分析方法对7例接受左甲状腺素（L-T4）替代治疗的重度甲状腺功能减退症患者进行了T4和T3的动力学研究。每位受试者在口服普萘洛尔治疗前和治疗期间接受了静脉推注的标记T4和T3混合示踪剂量。血清T4未发生变化，而血清T3显著下降了13%。T4和T3的处置率（DR）显著降低，在普萘洛尔治疗期间，T3的处置率与T4的处置率之比（转化率）显著降低。T4处置率的降低表明普萘洛尔治疗期间L-T4的生物利用度降低，可能是由于肠道吸收减少所致。转化率的降低表明普萘洛尔治疗期间甲状腺外T4向T3的转化减少。
