ABSTRACT
The general change in the connective tissues which occurs in animals with experimentally produced exophthalmos, consists in an increase in the amount of hyaluronic acid, which binds the water in the connective tissue. Many regard this process as a stimulation of the mucinous system in the connective tissues, and consider this an explanation of the phenomenon of exophthalmos. When the experimental animals are injected with thyroxine or thyroid extract, the reaction observed is opposite to that seen following the injection of the anterior lobe of the pituitary gland. In the former case, there is a reduction in the amount of hyaluronic acid and consequently a decrease in the water content in the connective tissues.
In the experiments in question, Na-d-thyroxine and Na-l-thyroxine), in crystalline form, were tested for their inhibiting effect on the development of exophthalmos in experimental animals. The animals used were male albino guinea-pigs. An extract of the anterior lobe of the pituitary gland (TSH Organon)) was used to produce exophthalmos. In previous work (Tengroth 1961), it was shown, using an X-ray measuring technique, that d-thyroxine, despite its poor caloric effect, like l-thyroxine had an exophthalmos-inhibiting effect. When comparing the dose-response curves of the exophthalmos-inhibiting properties of both these optical isomers, it appears that d-thyroxine has an inhibiting effect which is significantly greater than that of l-thyroxine.
The significance of this observation is discussed.
