Retention of skeletal fluoride during bone turnover in rats.
Deposition of fluoride (F) in the skeleton is a major factor in the metabolic regulation of F. The progressive increase in bone F levels with age suggests that F is rather firmly sequestered once it is deposited in bone. We have examined the extent to which F is resorbed and redeposited during bone turnover in growing rats. The skeleton was first preloaded with F by intake of water containing a high level of F (50 mg F/L) and simultaneously labeled with [3H]tetracycline (3H-TC) to provide a measure of subsequent bone turnover. Rats were then changed to a very low F intake, and bone F loss was compared with 3H-TC loss in animals undergoing normal bone turnover or turnover accelerated by a low calcium (Ca) intake. Approximately 60% of F mobilized during bone resorption was redeposited in the skeleton (humerus and vertebrae). The redeposition of F showed a positive correlation with mineral deposition. Thus the retention of F in the skeleton of growing rats results predominantly from redeposition of resorbed F rather than passive retention associated with low bone turnover.
Guo
M K
MK
Department of Oral Biology, School of Dentistry, University of Minnesota, Minneapolis 55455.
Nopakun
J
J
Messer
H H
HH
Ophaug
R
R
Singer
L
L
D000367:Age Factors; D000818:Animals; D001835:Body Weight; D001862:Bone Resorption / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism*; D002118:Calcium / Q000172:deficiency / Q000378:metabolism; D004032:Diet; D005459:Fluorides / Q000378:metabolism*; D051381:Rats
D005459:Fluorides; D002118:Calcium