Uranium in Bone: Metabolic and Autoradiographic Studies in the Rat

Abstract

<jats:p> The distribution and retention of intravenously injected hexavalent uranium-233 in the skeleton of the female rat has been investigated using a variety of autoradiographic and radiochemical techniques. These showed that approximately one third of the injected uranium is deposited in the skeleton where it is retained with an initial biological half-time of ∼40 days. The studies also showed that: </jats:p><jats:p> 1 Uranium is initially deposited onto all types of bone surface, but preferentially onto those that are accreting. </jats:p><jats:p> 2 Uranium is deposited in the calcifying zones of skeletal cartilage. </jats:p><jats:p> 3 Bone accretion results in the burial of surface deposits of uranium. </jats:p><jats:p> 4 Bone resorption causes the removal of uranium from surfaces. </jats:p><jats:p> 5 Resorbed uranium is not retained by osteoclasts and macrophages in the bone marrow. </jats:p><jats:p> 6 Uranium removed from bone surfaces enters the bloodstream where most is either redeposited in bone or excreted via the kidneys. </jats:p><jats:p> 7 The recycling of resorbed uranium within the skeleton tends to produce a uniform level of uranium contamination throughout mineralized bone. These results are taken to indicate that uranium deposition in bone shares characteristics in common with both the 'volume-seeking radionuclides' typified by the alkaline earth elements and with the 'bone surface-seeking radionuclides' typified by plutonium. </jats:p>

Pattern of Uptake of Americium-241 by the Rat Skeleton and its Subsequent Redistribution and Retention: Implications for Human Dosimetry and Toxicology

“…This tendency is indicated graphically in Figure 1 where the percentage change in the 241Am content of the different bone/bone groups (excluding the skull and mandibles) is shown as a function of its concentration in them at 1 day post-injection. However, the tendency is not marked (P = 0.11) as it is for some other radionuclides, eg, 233U (Priest et al, 1982), suggesting that systemic recycling of resorbed 241Am such as would tend to produce a uniform distribution of the radionuclide throughout the skeleton occurs only slowly if at all.…”

“…with osteoblasts. This may be regarded as surprising as the odontoblast, a similar cell, seems to accumulate 241Am, (Hammarstr6m & Nilsson, 1970) but is consistant with the findings for other actinide elements such as plutonium and uranium, (Priest et al, 1982).…”

“…The present studies, which include high resolution autoradiography are intended to examine in detail the deposition, redistribution and retention characteristics of 24' Am in the rat skeleton. They are the second in a series which compares the patterns of uptake and redistribution in bone of different heavy metals, (see also Priest et al, 1982). Methods .…”

A Model for Scaling the Results of U Excretion Rate Studies in Beagle Dogs to Man

“…Simulation model predictions of skeletal retention half-times were in closer agreement with injection studies in the human and rat than in the dog ( Table 7). The simulated clearance half-time, SO d, is somewhat longer than the value of 15-28 d for retention in humans (Struxness et al 1955;Adams and Spoor 1974) but is similar to the 40-to 45-d value observed in rats injected with uranyl nitrate (Priest et al 1982). Note that all these experiments were substantially shorter than the median lifetime of the species studied.…”

Complexation of U(VI) with highly phosphorylated protein, phosvitinA vibrational spectroscopic approach

“…In addition, the toxicity effects of uranium on blood transportation [5], kidney [6,7], bones [8], lung [9], skin, reproduction system [10], or in the embryo development [11] have been recently studied at a cellular level. Investigations were carried out to study the impact of uranium on the local biodiversity due to contamination of the environment [12,13].…”