THE RATES OF UTILIZATION OF THYROXINE AND OF DESICCATED THYROID IN MAN: THE RELATION BETWEEN THE IODINE IN DESICCATED THYROID AND IN THYROXINE

Open Access
Publisher Website
Google Scholar
Abstract
In two patients with marked myxedema and basal metabolisms of [long dash] 33 and [long dash]41%, respectively, the standard normal level of metabolism was maintained by: (1) injecting 0.3 mgm. (I content 02 mgm.) and 0.35 mgm. (I content 0.23 mgm.) Squibb''s crystalline thyroxine respectively intraven. or subcut. every day; (2) injecting 1.5 mgm. and somewhat less than 2 mgm. thyroxine respectively intraven. or subcut. every 5th day; (3) administering 1.25 grain (I content 0.19 mgm.) and 1.5 grain (I content 0.23 mgm.) desiccated thyroid respectively, by mouth daily. It appears that in the presence of a marked thyroid deficiency 10 mgm. of thyroxine has about the same effect whether given in a single dose or in divided daily doses of 0.3 mgm. Thus thyroxine which merely replaces a deficiency in the body is used almost quantitatively. These facts are consistent with the hypothesis that practically all the I in desiccated thyroid is in a form physiologically equivalent to thyroxine, and that, when the amount administered is not more than adequate to replace a deficiency, it is absorbed almost quantitatively from the gastrointestinal tract. The best method of standardizing desiccated thyroid would seem to be the determination of its total I content.