QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Frankel, T. L. Articles by Cornish, C. J. Search for Related Content PubMed PubMed Citation Articles by Frankel, T. L. Articles by Cornish, C. J.

Hypervitaminosis A and Calcium-Regulating Hormones in the Rat^1,2,

Departments of Nuclear Medicine and Endocrinology, Royal North Shore Hospital, St. Leonards, N.S.W., 2065, Australia

The effect of vitamin A on calcium-regulating hormones was studied in rats. A single oral dose of 30 mg retinol equivalents (RE) given to adult rats caused no change to serum biologically active parathyroid hormone (bioactive-PTH) concentrations. Bioactive-PTH secretion from rat thyroparathyroid gland complexes was not significantly altered after in vitro incubation with 1.18 x 10^-6 M retinol. Chronically intoxicated rats given 15 mg RE 3 times a week for 6 wk, showed higher osteoclast numbers and lower osteoid than controls. Serum bioactive-PTH was not detectable and serum 25-hydroxyvitamin D (25-OHD) (25.2 ± 12.5 nmol/L) was significantly (P < 0.03) lower than controls (43.3 ± 3.1). In acutely intoxicated rats (60 mg RE/d for 2 d), serum bioactive-PTH levels were significantly lower (0.02 ± 0.05 ng/ml, P < 0.03) than in control animals (0.14 ± 0.08). Lower doses of vitamin A, 7.5 mg RE 3 times a week for 3 wk, suppressed serum bioactive-PTH to undetectable levels but had no significant effect on serum 25-OHD. Serum calcium and 25-OHD levels were significantly lower in vitamin D-intoxicated rats given 7.5 mg RE 3 times a week (ca. 3.16 ± 0.19 mmol/L; 25-OHD 599.7 ± 110.6 nmol/L) than vitamin D-intoxicated controls (3.42 ± 0.17; 789.3 ± 17.7). These results suggest that hypervitaminosis A can alter the metabolism of calcium-regulating hormones.

KEY WORDS: • vitamin A • parathyroid hormone • hypervitaminosis • bone

¹ This work was supported by the National Health and Medical Research Council of Australia.

² Presented in part at the 9th Annual Conference of the Nutrition Society of Australia, Armidale, Australia, Nov. 1984. Frankel, T. L., Seshadri, M. S., McDowall, D. B. & Posen, S. (1984) Vitamin A intoxication in the rat: effect on parathyroid hormone. Proc. Nutr. Soc. Aust. 9, 123 (abs.).

³ Present address: Department of Animal Husbandry, University of Sydney, Sydney, N.S.W., Australia, 2006.

⁴ Present address: Dept. of Medicine, Unit II, CMC Hospital, Vellore, Tamil Nadu, India, 632004.

Manuscript received 13 August 1985. Revision accepted 26 November 1985.

This article has been cited by other articles:

				M. Hogstrom, A. Nordstrom, and P. Nordstrom 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 Eur. J. Endocrinol., May 1, 2008; 158(5): 765 - 770. [Abstract] [Full Text] [PDF]

				K. L Penniston, N. Weng, N. Binkley, and S. A Tanumihardjo Serum retinyl esters are not elevated in postmenopausal women with and without osteoporosis whose preformed vitamin A intakes are high Am. J. Clinical Nutrition, December 1, 2006; 84(6): 1350 - 1356. [Abstract] [Full Text] [PDF]