science · 25 December 1914 · 110 years ago
In 1914, the thyroid hormone, thyroxine, was first crystallized by biochemist Edward C. Kendall of the Mayo Foundation in Rochester, NY. Thyroxine controls the cellular rate of carbohydrate metabolism and of protein synthesis and breakdown. On Dec 23, he began evaporating an ethanol solution of a sample of the acid-insoluble fraction of thyroid glands removed surgically from patients. It left a white crust surrounded by a ring of yellow waxy material. Adding ethanol now redissolved the waxy material, but not the white crust. On Christmas Day, he dissolved some of the white crust in ethanol and sodium hydroxide. A few drops of acetic acid precipitated crystals. This throxine was fully active in relieving the symptoms of thyroid deficiency in hypothyroid patients.
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