Mineralization, bone rats, effect

Stanimirova I. Michalik K. Drzazga Z. Trzeciak H. Wentzell P.D. Walczak B. Interpretation of analysis of variance models using principal component analysis to assess the effect of a maternal anticancer treatment on the mineralization of rat bones. Analytica Chimica Acta, 2011,689 (1), 1-7. 

Studies in rats have shown effects of lead on bone mineralization and bone growth. The effects observed in rats may be relevant to our understanding of the mechanisms for the growth deficits that have been associated with low-level in utero and childhood lead exposures. Additional studies of the effects of lead on bone metabolism in humans and in animal models would improve our understanding of the toxicological significance of lead in bone. 

Diaz Curiel M, Calero JA, Guerrero R, Gala J, Gazapo R, de la Piedra C (1998) Effects of LY-117018 HC1 on bone remodeling and mineral density in the oophorectomized rat. Am J Obstet Gynecol 178 320-325... 

LiX, Takahashi M, Kushida K, Inoue T (1998) The preventive and interventional effects of raloxifene analog (LY117018 HC1) on osteopenia in ovariectomized rats. J Bone Miner Res 13 1005-1010... 

Sato M, McClintock C, Kim J, et al. (1994) Dual-energy X-ray absorptiometry of Raloxifene effects on the lumbar vertebrae and femora of ovariectomized rats. J Bone Miner Res 9 715-724... 

Williams DC, Paul DC, Black LJ (1991) Effects of estrogen and tamoxifen on serum osteocalcin levels in ovariectomized rats. Bone Miner 14 205-220... 

Recently, a Japanese research group published preclinical safety and efficacy data of an oral antiestrogen (TZE-5323) (Saito et al. 2003). This drug has been shown to have a strong affinity for human ERa and ER/i and a dose-dependent capacity to inhibit estradiol-stimulated transcriptional activation (Saito et al. 2003). In the experimental endometriosis model in rats, TZE-5323 dose-dependently reduced the volume of the endometrial implant with an effectiveness similar to that of danazol and leuprorelin acetate without causing significant changes in bone mineral density and in serum estradiol levels (Saito et al. 2003). 

Table II shows the effects of varying dietary levels of zinc on weight gains and on bone calcium and phosphorus levels of young rats at the end of a 4-week experiment. Increases in dietary zinc were associated with significant linear decreases in bone calcium and phosphorus deposition. The bones taken from animals at the time of sacrifice and used for the mineral analyses were very soft in nature and could be easily squeezed with the fingers.

Table I. Effects of Zinc on Growth and Young Rats Bone Mineralization of ...

Table III. Effects of Calcium, Phosphorus, and Zinc Supplements on Growth and Bone Mineralization of Young Rats...

The data presented in this paper indicate that excess levels (0.75%) of dietary zinc result in decreases in the bioavailability of calcium and phosphorus in rats and interfere with normal bone mineralization. High dietary levels of calcium or zinc appeared to cause a shift in the excretion of phosphorus from the urine to the feces, while the presence of extra phosphorus tended to keep the pathway of phosphorus excretion via the urine. The presence of large amounts of phosphorus in the Intestinal tract due to high intakes of zinc would increase the possibility of the formation of insoluble phosphate salts with various cations, including calcium, which may be present. A shift in phosphorus excretion from the feces to the urine, however, could result in an environmental condition within the system which would tend to increase the bioavailability of cations to the animal. The adverse effect of zinc toxicity on calcium and phosphorus status of young rats could be alleviated with calcium and/or phosphorus supplements. 

A number of nutrients affect bone integrity early in life. While the role of certain minerals and vitamins bearing on skeletal integrity is well established, that of protein remains controversial, especially when consumed in excessive amounts. Protein-included calciuric effect as observed in adult man and animals may also occur early in life and thus conceivably affect peak bone mass adversely, particularly when calcium intakes may be marginal. In studies reported here (test model young female rats), it was found that a diet approaching adequacy in protein and based equally on plant and animal sources would favor some parameters which bear on skeletal mass at maturity more than other combinations of protein consumed. 

Sato M, Grasser W. Effects of bisphosphonates on isolated rat osteoclasts as examined by reflected light-microscopy. J Bone Miner Res 1990 5 31-40. 

Rao, L.G., Krishnadev, N., Banasikowska, K., and Rao, A.V. 2003. Lycopene I—Effect on osteoclasts Lycopene inhibits basal and parathyroid hormone-stimulated osteoclast formation and mineral resorption mediated by reactive oxygen species in rat bone marrow cultures. J. Med. Food 6, 69-78. 

The mean pretreatment values of bone mineral density (BMD) measured in vivo by DEXA during the acclimation period at the lumbar spine, total body skeleton, and femoral site were 0.148 0.003g/cm2, 0.118 0.001 g/cm2, and 0.245 0.004 g/cm2, respectively. The BMD of the lumbar spine was 19% lower in OVX control rats than in intact controls (p <. 01) (Labrie et al, 1999). The animals given EM-800 or raloxifene at doses of 0.01-1 mg/kg had 90 to 93% and 85 to 90%, respectively, of the BMD observed in intact rats, the BMD values being significantly higher than those of OVX control rats (p <. 01), with the exception of the lowest dose of raloxifene (0.01 mg/kg), which did not have a statistically significant effect on this parameter. The lumbar spine BMD of rats treated with Eg was 92% (p <. 01) of that observed in the... 

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