Vitamin D and Its Hydroxylated Metabolites in the Rat

Noff, Dina; Edelstein, S.

doi:10.1159/000178924

Cited by 82 publications

(10 citation statements)

References 5 publications

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“…Similar findings have been reported for man [4]. The finding that 24,25(Ow2D3, a metabolite of vitamin D that, like 1,25(OH)2D3, is formed in the kidney [12-131 and accumulates in foetal rat bones [14] and in chick calluses [5], suggests that this metabolite also is essential for normal bone formation [3]. The results of the present study tend to confirm these previous findings.…”

supporting

confidence: 91%

The Effect of Vitamin D and Its Metabolites on Fracture Repair in Chicks

1983

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One-day-old chicks were depleted of vitamin D. At 3 weeks their right tibiae, and those of a control group given vitamin D3, were fractured and pinned. After fracture the controls were kept on vitamin D3. Another group was left vitamin D-deficient. The remaining depleted chicks, divided into four groups, were given vitamin D3, 24,25-dihydroxyvitamin D3 [24,25(OH)2D3], 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] or a combination of 24,25(OH)2D3 and 1,25(OH)2D3. The callus obtained after 9 and 14 days was subjected to torsional stress. The callus of chicks given vitamin D continuously showed the greatest resistance, whereas that of vitamin D-deficient chicks showed the smallest resistance. Repletion with either vitamin D3 or its metabolites increased the strength of the callus. Repletion with the combination of 24,25(OH)2D3 and 1,25(OH)2D3 produced the most marked results, in that the callus was even stronger than that of chicks replete with vitamin D3. It is concluded that 24,25(OH)2D3 is essential for bone formation in addition to the known active vitamin D metabolite 1,25(OH)2D3, and the possible clinical implications of these findings are discussed.

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confidence: 91%

The Effect of Vitamin D and Its Metabolites on Fracture Repair in Chicks

1983

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“…Generally speaking hydroxylation at the 24 position of vitamin D has been shown to reduce the biological activity of the molecule and may represent the initial step in a degradative pathway (26,27). On the other hand it has been suggested that 24,25-(OH)2D is important in bone mineralization (28), suppression of parathyroid hormone secretion (29), and embryonic development (30,31 Vitamin D Metabolism in the Rat Pup. Calcium and phosphorus requirements for growth and skeletal development are enormous in the growing rat and it would be expected that the vitamin D endocrine system would be shifted in such a direction as to maximally stimulate calcium transport in the intestine and bone formation.…”

Section: Resultsmentioning

confidence: 99%

Vitamin D metabolism during pregnancy and lactation in the rat.

Halloran¹,

Barthell²,

DeLuca³

1979

Proc. Natl. Acad. Sci. U.S.A.

138

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The plasma concentration of the major vitamin D metabolites; 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and 24,25-dihydroxyvitamin D were measured during pregnancy and lactation in the adult female rat. The concentrations of these metabolites were also measured in rat pups during lactation and after weaning.. The plasma concentration of 1,25-dihydroxyvitamin D in the adult female increases from a control value of 26 pg/ml to 86 pg/ml during the latter stages of pregnancy, reaches a peak of 158 pg/ml during lactation, and then returns to control levels by 3 weeks postweaning. Plasma concentrations of 24,25-dihydroxyvitamin D fall dramatically during pregnancy from a control level of 3.9 ng/ml to 1.6 ng/mI remain low during lactation, and return to control levels by 3 weeks postweaning. In the neonatal rat pup at 14 days postpartum, 1,25-dihydroxyvitamin D plasma concentration is 25 pg/ml and 24,25-dihydroxyvitamin D concentration is 2.8 ng/ml. By day 25 postpartum, 1,25-dihydroxyvitamin D concentrations reached levels of 101 pg/ml, whereas 24,25-dihydroxyvitamin D concentrations fell to 1.9 ng/ml.The metabolism of vitamin D and its involvement in normal calcium/phosphate metabolism are well documented (1-5). Dietary changes in calcium and phosphate are compensated for by changes in the vitamin D endocrine system in such a way as to maintain a normal calcium and phosphate balance.Pregnancy and lactation bring about dramatic changes in the calcium/phosphate homeostatic mechanism (6). Intestinal calcium transport (7) and bone resorption (8) increase to meet fetal and neonatal calcium and phosphate requirements. The subsequent changes in vitamin D metabolism, however, have not been exhaustively described. Recent reports indicate that the most active hormonal form of vitamin D, 1,25-dihydroxyvitamin D [1,25-(OH)2D], is increased during pregnancy and lactation (9, 10). There is also strong evidence that there are fundamental differences between maternal and fetal metabolism of vitamin D (11). These findings underscore the importance of establishing the plasma concentrations of the major vitamin D metabolites and their relation to each other during pregnancy and lactation. In this paper we report the plasma concentrations of 25-hydroxyvitamin D (25-OH-D), 1,25-(OH)2D, and 24,25-dihydroxyvitamin D [24,2D] during pregnancy, lactation, and the postweaning period in the adult rat as well as the levels of these metabolites in the neonatal rat pup. MATERIALS AND METHODSFemale Holtzman rats (Holtzman Rat Co., Madison, WI) were obtained as weanlings and maintained on a diet containing 0.44% calcium and 0.30% phosphorus (12). In addition, animals were given 25 international units of vitamin D per day in 0.1 ml of cottonseed/soybean oil (Wesson). At 130 days of age, the females were mated with normal male breeders from Holtzman. The presence of sperm in vaginal smears was used to establish the first day of pregnancy.At days 18 and 20 of pregnancy, at day 14 of lactation, at the time of weaning which was set at 25 days ...

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“…Vitamin D compounds will cross the placental barrier, and differences in the maternal and fetal metabolism of vitamin D have been reported [9][10][11]. The placenta is also capable of converting 25-hydroxyvitamin D3 (25-OH-D3) to 1,25(OH)2D3, suggesting that this organ may play a major role in vitamin D metabolism during reproduction and may influence the levels of vitamin D in the fetus [12,13].…”

mentioning

confidence: 99%

Studies on the role of vitamin D in early skeletal development, mineralization, and growth in rats

et al. 1983

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Summary.The role of vitamin D in early skeletal development was studied by measuring serum calcium and phosphorus, osseous tissue quantity and mineralization, and endochondral bone elongation in rat fetuses and pups from vitamin D-replete and vitamin D-deficient mothers. At the 20th day of pregnancy there was a slight, yet significant, increase in the amount of osteoid on trabecular bone surfaces in fetuses from vitamin D-deficient mothers. The fetal bones otherwise appeared normal in spite of severe skeletal changes in the vitamin D-deficient mothers. After parturition, the importance of vitamin D in skeletal development becomes progressively more obvious. Serum calcium levels were slightly, yet significantly, lower in vitamin D-deficient than in vitamin D-replete pups and these levels continued to tall in the vitamin D-deficient pups through lactation and after weaning. At 3 days postpartum, there was a small, yet significant, increase in the amount of osteoid on bone surfaces of the vitamin D-deficient pups. The relative amounts of osteoid in the vitamin D-deficient pups continued to increase through lactation and after weaning when compared with vitamin D-replete pups. By the 14th day of lactation and at later periods, there were significant reductions in metaphyseal mineralized tissues in the vitamin D-deficient pups when compared with the vitamin D-replete pups. At weaning and after weaning, there were substantial increases in growth plate thickness and decreases in longitudinal bone growth in the vitamin D-deficient pups when compared with the vitamin D-replete pups. The results from this study indicate that vitamin D does not appear to play a major role in fetal skeletal development. However, after birth, vitamin D becomes progressively more important with age for normal bone development, mineralization, and endochondral growth.

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Vitamin D and Its Hydroxylated Metabolites in the Rat

Cited by 82 publications

References 5 publications

The Effect of Vitamin D and Its Metabolites on Fracture Repair in Chicks

The Effect of Vitamin D and Its Metabolites on Fracture Repair in Chicks

Vitamin D metabolism during pregnancy and lactation in the rat.

Studies on the role of vitamin D in early skeletal development, mineralization, and growth in rats

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