[Determination of triiodothyronine intake in the retrograde perfused Langendorff rabbit heart. A study of the binding capacity and distribution in subcellular fractions].

In an experimental set after Langendorff hearts of rabbits are retrogradely perfused and the myocardial intake of 125J T3 depending on the T3-concentration under oxygenation, hypoxia and cardioplegy is estimated. With the help of a discontinuing saccharose gradient after electron microscopic differentiation of the stratifications the identification of the subcellular bindings of the 125J-T3 taken was performed. It was shown that under our experimental conditions the heart possesses a large intake capacity for free T3, in which case the value established of 115.42 ng T3/g of heart tissue could be achieved under unphysiologically high offer of T3. An influence of the hypoxia and cardioplegy on the intake of T3 was proved and the possibilities of the increased T3-binding were discussed. The clinical phenomenon of a decrease of T3 in myocardial infarction could experimentally be proved by an increased T3-extraction under hypoxia.