Dear Thyroid Friends,
Dr. David Derry sent me a copy of this recent
research. I thought that all the Armour fans in the audience would enjoy this
bit of trivia:
<quote>
Dear Dr. Toft.
I have been admirer of your work since your 1991 entry in Werner's The
Thyroid. Your article in that book was by far the most informative and
interesting over all the others.
I have been reading one of your recent publications.
Is excessive weight gain after ablative treatment of hyperthyroidism due
to inadequate thyroid hormone therapy? Tigas, S. Idiculla, J. Beckette,
G. and Toft A.
In that article it is said:
"It would be wrong to advocate a return to the use of animal
thyroid extract that contains both hormones, as the potency of these
tablets is very variable. This is the reason they were replaced by the
use of synthetic T4 starting in the 1960s."
Dr Toft this statement lacks knowledge of the true events of the sixties
and seventies.
Goodman and Gilman The Pharmacological Basis of Therapeutics Fourth
edition. MacMillan Company London 1970. page 1479 Right hand column
Paragraph 3.
"Thyroid U.S.P., it is highly satisfactory preparation for
clinical use. Its continual popularity does not derive merely from a
reactionary attitude, although at first sight the preparation might seem
to be crude, old-fashioned, and poorly standardized. It is evidently
uniformly well absorbed unless it has an enteric coating, and the
potency is sufficiently standard that variation cannot be detected
clinically if the official preparation is prescribed."
"A few years ago, a large batch of material came into the hands
of a number of distributors in the United States and Europe and,
although of proper iodine content, it later proved not to be thyroid at
all. This episode gave thyroid a bad name because several publications
about the unreliablilty of thyroid appeared before the hoax was
uncovered."
Dr. Toft the hoax was in 1963.
L. E. Braverman and S. H. Ingbar. Anomalous effects of certain
preparations of dessicated thyroid on serum protein bound iodine. N Engl
J Med 270:439-442, 1964.
Ten years later synthyroid had captured 84 % of the United
states market.
The pharmacology of Synthroid and related levothyroxine
compounds is as follows.
Goodman and Gilman The Pharmacological Basis of Therapeutics Forth
edition. 1970 page (1479. Left hand column last paragraph. (under choice
of preparations)The same statement is made in the Eighth edition 1990
page 1371.
Choice of preparation: levothyroxine
"The pure compounds carry the attraction of single, reproducible
substances of known and constant composition. When thyroxine was first
used orally in man, it was considered to be poorly absorbed"....../
"There is still some evidence that absorption of sodium levothyroxine is
variable and incomplete, as much as 30 to 40% being recoverable in the
stool. Depending upon the form in which it is given, the proportion of
a single oral dose absorbed may vary from 42 to 74%, this fraction is
rapidly absorbed, while the rest traverses the intestine in a bound
unabsorbable form. Nevertheless, sodium levothyroxine has been
extensively used with satisfaction and is widely held to be superior to
thyroid because of better standardization and stability."
From the same authority. 1990 Eighth Edition Page 1371 first Column
Bottom paragraph.
Preparations. Thyroid is a fine powder made from the thyroid of animals,
usually pigs, by defatting and drying with acetone. The USP specifies
that the content of iodine be between 0.17 and 0.23% and as most thyroid
powders are stronger than this, they are diluted with an enert material.
Although neither bioassay nor chemical analyses for thyroxine or
triiodothyronine are specified, the product is remarkably uniform.
Goodman and Gilman The Pharmacological Basis of Therapeutics Sixth
Edition 1990. page 1407 Column one second paragraph: Under Comparative
Responses to thyroid preparations. "There is no significant difference
in the qualitative response of the patient with myxedema to
triiodothyronine, thyroxine or thyroid."
Nor are there any other published reports of variablility in Thyroid
extract since the early 1920s when it was standardized except for the
one hoax in 1963.
Hope these quotes are of interest to you as they seem to explain much
that happened in the 1960s and 1970s and we are still dealing with this
now.
Sincerely,
David Derry
MD PhD
<end of quote>
Doc Don
_______________________________________________________________
Snip, Please
If you "Reply" to a message, and *you* fail to erase or delete
the previous message, *your* message cannot be distributed.
Why not ask a question? If we're not currently talking about
what *you* want to hear about, ask about another topic! Or
make a statement. To be prepared, you might want to search
the Thyroid Archives http://www.Emissary.Net/thyroid/index.html
to see what has been said before about any thyroid-related topic.
_______________________________________________________________
|
