Observations on M⊘rch's Method for Standardization of Thyroid Gland Preparations

M⊘rch 1 devised a method for the standardization of thyroid preparations based on the percentage increase of the carbon dioxide output of white mice after administration of thyroid preparations. Gaddum and Hetherington 2 compared the physiological activity of thyroid preparations with the thyroxine content as determined by Harington and Randall. 3 It seemed desirable to investigate the question whether the thyroid glands of patients with exophthalmic goiter contained some substance other than thyroxine itself which might cause an increase in the basal metabolic rate. An answer seemed possible by feeding animals equi-thyroxine doses of different gland preparations obtained from patients with Graves' disease and from normal individuals. If the physiological activity of the 2 types of preparations proved to be the same, this might be considered evidence that the increase in basal metabolism characteristic of Graves' disease could be accounted for by the thyroxine content alone. It would then be unnecessary to postulate the presence of any other toxic substance. The method developed by M⊘rch was chosen since it has the necessary feature that small amounts of material can be employed. Normal thyroid preparations from the series of Leland and Foster 4 and exophthalmic goiter preparations from the series of Gutman, Benedict, Baxter and Palmer 5 were used. All glands were analyzed by the method of Leland and Foster. The optimal experimental conditions worked out by M⊘rch were closely adhered to and it was found that the carbon dioxide output of the mice could be determined with the degree of precision which he claims (Table I). The commercial thyroid preparation used as a standard (Burroughs Wellcome & Co.) was first administered by mixing dry with the food as directed by M⊘rch.