UNIVERSITY OF innéesota

 

 

DEPARTMENT OF BIOCHEMISTRY

227 MILLARD HALL - MINNEAPOLIS, MINNESOTA 55458
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SIM Y/ J May 27, 1969

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Professor Joshua Lederberg

Department of Genetics

Stanford University School of Medicine
300 Pasteur Drive

Palo Alto, California

Dear Professor Lederberg:

I transmit to you herewith, as your requested, reprints of some of our
papers on fluoride metabolism. I hope that these will be of interest and of
use to you.

With respect to your question of genetic variation, I can say that I know
nothing on this score. There are, however, some differences in fluoride
metabolism between species of animals. For example, a much higher relative
intake of fluoride is required to produce mottled enamel in the rat than in
the human. This is because the rat incisor tooth grows continually through
life. Also the skeleton of the rat continues to grow virtually through the
life of the animal.

Although there may very well be a special fluoride-binding protein in
plasma, no one has yet defined it. The evidence at the moment is that the
total fluoride of plasma exceeds by almost a half an order of magnitude the
ionic fluoride of plasma. However, I am not yet certain that the non-ionized
fluoride is directly combined with any bare plasma protein. This is a problem
on which we are now working, but we have not yet obtained any clear or
definitive evidence.

“9(L00LLS WY

I had earlier seen your article on fluoridation. With respect, to the
point you mentioned in the next to the last paragraph, I can indicate that
careful and thorough studies by Dr. Herta Spencer of the Hines Veterans
Hospital have shown, with very wide variations of calcium intake, no appreciable
difference in the amount of fluoride absorbed from the intestine in humans.

Less than 10% of the fluoride intake, which was also varied, was present in
the feces.

Yours Dd,

(VW D. Armstrong oo

Professor and Head
WDA /bah

HEALTH SCIENCES CENTER
MEDICAL SCHOOL