Hypervitaminosis A and Calcium-Regulating Hormones in the Rat

Frankel, Theresa L.; Seshadri, M. S.; McDowall, D.; Cornish, Coralie J.

doi:10.1093/jn/116.4.578

Cited by 47 publications

(33 citation statements)

References 38 publications

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“…Interestingly, the time course, dose response, and relative magnitude of the retinoid-mediated effect at both the PTH peptide and preproPTH mRNA levels closely parallel the inhi- (Fig. 4) ( 17) showed reduced serum PTH in rats administered high doses of retinoids suggesting that hypervitaminosis A may suppress PTH expression in vivo. That study was complicated by hypercalcemia in the vitamin A-intoxicated animals, presumably caused by the effects of vitamin A on bone and its ability to mobilize bone calcium (25)(26)(27)(28).…”

Section: Discussionmentioning

confidence: 69%

Retinoic acid suppresses parathyroid hormone (PTH) secretion and PreproPTH mRNA levels in bovine parathyroid cell culture.

MacDonald¹,

Ritter²,

Brown³

et al. 1994

J. Clin. Invest.

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1,25-dihydroxyvitamin D3 11,25(OH)2D31 suppresses parathyroid hormone (PTH) gene transcription. Recent evidence suggests that retinoid X receptors are involved in 1,25(OH)2D3-mediated transcriptional events. However, little data exists for a role of retinoids in parathyroid function or in PTH expression. In the present study, we observed that all-trans-or 9-cis retinoic acid suppressed the release of PTH from bovine parathyroid cell cultures. Both retinoids were remarkably potent with significant decreases evident at 10-10 M and a maximally suppressive effect (-65%) at 10'-M. All-trans-retinol was considerably less potent in this system. The effect was not evident until 12 h, suggesting that retinoids did not affect the rapid secretion of preexisting PTH stores. PreproPTIH mRNA levels were also suppressed by retinoic acid and the retinoid potencies were similar to those observed in the secretion studies. Combined treatment with 10-6 M retinoic acid and 10-8 M 1,25(0H)2D3 more effectively decreased PTH secretion and preproPTH mRNA than did either compound alone. These data indicate that retinoic acid: (a) elicits a bioresponse in bovine parathyroid cells; (b) attenuates PTH expression at the protein and mRNA levels, and (c) acts independently of 1,25(OH)2D3 in the control of PTH expression. (J. Clin. Invest. 1994. 93:725-730.)

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Section: Discussionmentioning

confidence: 69%

Retinoic acid suppresses parathyroid hormone (PTH) secretion and PreproPTH mRNA levels in bovine parathyroid cell culture.

MacDonald¹,

Ritter²,

Brown³

et al. 1994

J. Clin. Invest.

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“…These results are of interest also with respect to the present study, since vitamin A has been suggested to antagonize vitamin D's positive influence on bone mineralization and calcium uptake (23,(36)(37)(38). We therefore also investigated whether levels of vitamin A and RBP-4 were associated with levels of vitamin D presented in a previous study (19).…”

Section: Discussionmentioning

confidence: 70%

Retinol, retinol-binding protein 4, abdominal fat mass, peak bone mineral density, and markers of bone metabolism in men: the Northern Osteoporosis and Obesity (NO2) Study

Högström

Nordström

2008

European Journal of Endocrinology

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Context: The association between retinol and bone mineral density (BMD) in males after puberty has not been fully investigated previously. Objective: To investigate the association between retinol, retinol-binding protein-4 (RBP-4), BMD (g/cm 2 ), abdominal fat mass, and markers of bone metabolism in young men. Design: Longitudinal study. Participants: Seventy-eight healthy males with a mean age of 22.6G0.7 years at baseline. A follow-up was conducted in 73 of the participants 2.0G0.4 years later. Main outcome measures: Associations between serum concentrations of retinol and RBP-4, and BMD of the total body, lumbar spine, and hip, serum concentrations of osteocalcin, and carboxy terminal telopeptide of type 1 collagen (CTX), were investigated. Results: Both retinol and RBP-4 showed an inverse relationship with that of osteocalcin (rZK0.23 to K0.25, P!0.05). Levels of RBP-4 (rZ0.26, PZ0.02) and osteocalcin (rZK0.23, PZ0.04) were also related to abdominal fat mass, and the relationship between RBP-4, retinol, and osteocalcin disappeared after adjusting for this influence of abdominal fat mass. Neither retinol nor RBP-4 concentrations were associated with BMD at any site, CTX as baseline, or changes in BMD during the 2-year follow-up period. Levels of RBP-4 showed a strong association with levels of retinol (rZ0.61, P!0.001). Conclusion: We found a negative association between the bone formation marker osteocalcin with retinol and RBP-4. The association disappeared when adjusting for the influence of abdominal fat mass. Neither retinol nor RBP-4 were associated with peak BMD in young men. 158 765-770 European Journal of Endocrinology

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“…Thus, there have been numerous animal studies demonstrating that a prolong excessive intake of vitamin A can cause ossification of cartilage, increased bone resorption, extraosseous calcification, hypercalcaemia, and suppressed parathyroid hormone levels [23][24][25]. More recently, there have been many cross-sectional studies (Table 3), which have compared the dietary intake of retinol and Bone Mineral Density (BMD).…”

Section: Toxicological Implications Of Elevated Hepatic Storage Of VImentioning

confidence: 99%

Significance of Vitamin A (Retinol) in Ageing

Basu¹

2011

TONUTRAJ

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Summary:In recent years, studies involving animal models, case reports, and some epidemiological studies have indicated that an accumulation of vitamin A in the liver is linked to low bone mineral content, fracture risk, and hence osteoporosis. While vitamin A in its physiological level acts as an inducer of bone matrix protein (osteocalcin) and matrix GLA protein in the osteoblast cells (bone formation), excess reinoic acid (a metabolic product of vitamin A) supresses osteoblastic activity and stimulates osteoclast formation (bone degradation). There also appear to have an antagonistic or synergistic interactions between vitamins A and D, influencing bone metabolosm; such effects are dose related. These effects could be of concern, especially for the older persons, because of the age-associated cumulation of vitamin A in the liver. The vitamin A status in elderly population, however, has not been as well documented as in an earlier age. In effect, the Food and Nutrition Board of National Academy's Institute of Medicine has not made any differenciation in it's recommendation for the Dietary Reference Intake (DRI) of vitamin A between 14 years and >70 years old individuals. This report will delineate the ageing differences in metabolic availability of vitamin A and that such differences are independent of its intake. The report will also attempt to formulate a hypothesis that in old age, deficiency of vitamin A is not a concern but its potential toxicity involving bone.

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Hypervitaminosis A and Calcium-Regulating Hormones in the Rat

Cited by 47 publications

References 38 publications

Retinoic acid suppresses parathyroid hormone (PTH) secretion and PreproPTH mRNA levels in bovine parathyroid cell culture.

Retinoic acid suppresses parathyroid hormone (PTH) secretion and PreproPTH mRNA levels in bovine parathyroid cell culture.

Retinol, retinol-binding protein 4, abdominal fat mass, peak bone mineral density, and markers of bone metabolism in men: the Northern Osteoporosis and Obesity (NO2) Study

Significance of Vitamin A (Retinol) in Ageing

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