AJP - Endocrinology and Metabolism, Vol 251, Issue 6 670-E673, Copyright © 1986 by American Physiological Society
Uptake, distribution, and excretion of 31silicon in normal rats
A. J. Adler, Z. Etzion and G. M. Berlyne
This study examines the uptake, distribution, and excretion of 31-labeled
silicic acid in rat tissues at 1, 2, and 4 h after intracardiac injection
of 31Si(OH)4. Plasma levels of 31Si decrease rapidly from 0.71 +/- 0.04% at
1 h to 0.07 +/- 0.06% of the dose administered per milliliter at 4 h. 31Si
in plasma was found to be virtually entirely nonprotein bound. Kidney,
liver, and lung accumulated the greatest amounts of 31Si per gram of wet
weight, with concentrations at 4 h suggesting both relatively avid uptake
and retention. Bone, skin, spleen, muscle, and testes also accumulated
31Si, but the levels were considerably lower than the aforementioned
organs. Brain, however, contained negligible concentrations of 31Si
throughout the study, indicating active exclusion by the blood-brain
barrier. The major portion of the administered 31Si, 77 +/- 12%, was
recovered in the urine within 4 h.
