DOES THE BLOOD OF PATIENTS WITH EXOPHTHALMIC GOITRE CONTAIN ACTIVE DERIVATIVES OF THE THYROID?

¹ The Department of Physiology, University, Edinburgh

The serum of normal human blood contains a substances which produces marked augmentation and acceleration of the contractions of an isolated strip of longitudinal muscle of cat's intestine (ileum).

The effect of serum from cases of exophthalmic goitre is far greater than that of serum from normal blood.

Thyroid extract also produces augmentation and acceleration of the contractions of the intestinal strip. It might therefore be inferred that in exophthalmic goitre there is a large amount of thyroid secretion present in the blood.

But the action of thyroid extract is relatively slight compared with that even of normal serum, and the specific autacoid of the thyroid (thyroxin) has no effect upon the intestinal strip. Moreover, neither normal blood nor exophthalmic blood, when fed to tadpoles, have any influence upon their metamorphosis.

These experiments therefore lend no support to the view that normal thyroid secretion containing thyroxin is poured into the blood in appreciably increased amount in exophthalmic goitre. Nor do they support the view that the symptoms of the disease are due to the presence of an abnormal amount of free adrenalin in the blood, since if this were the case the contractions of the intestinal strip would tend to be inhibited instead of being augmented.

Experiments are in progress to determine whether variations in the amount of augmentor substance in serum are characteristic of affections other than exophthalmic goitre, and if possible to isolate this substance and elucidate its nature.

The expenses of this research have been assisted by grants from the Earl of Moray Fund of the University of Edinburgh and from the Carnegie Trust for the Universities of Scotland.