Vitamin D3 Treatment Alters Thyroid Functional Morphology in Orchidectomized Rat Model of Osteoporosis |
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| Authors: | Branka &#x;o&#x;i&#x;-Jurjevi&#x; Svetlana Trifunovi&#x; Jasmina
ivanovi&#x; Vladimir Ajdanovi&#x; Marko Miler Nata&#x;a Risti&#x; Branko Filipovi&#x; |
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| Affiliation: | Institute for Biological Research “Siniša Stanković”—National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, 11060 Belgrade, Serbia; (S.T.); (J.Ž.); (V.A.); (M.M.); (N.R.); (B.F.) |
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| Abstract: | Vitamin D plays an essential role in prevention and treatment of osteoporosis. Thyroid hormones, in addition to vitamin D, significantly contribute to regulation of bone remodeling cycle and health. There is currently no data about a possible connection between vitamin D treatment and the thyroid in the context of osteoporosis. Middle-aged Wistar rats were divided into: sham operated (SO), orchidectomized (Orx), and cholecalciferol-treated orchidectomized (Orx + Vit. D3; 5 µg/kg b.m./day during three weeks) groups (n = 6/group). Concentration of 25(OH)D in serum of the Orx + Vit. D3 group increased 4 and 3.2 times (p < 0.0001) respectively, compared to Orx and SO group. T4, TSH, and calcitonin in serum remained unaltered. Vit. D3 treatment induced changes in thyroid functional morphology that indicate increased utilization of stored colloid and release of thyroid hormones in comparison with hormone synthesis, to maintain hormonal balance. Increased expression of nuclear VDR (p < 0.05) points to direct, TSH independent action of Vit. D on thyrocytes. Strong CYP24A1 immunostaining in C cells suggests its prominent expression in response to Vit. D in this cell subpopulation in orchidectomized rat model of osteoporosis. The indirect effect of Vit. D on bone, through fine regulation of thyroid function, is small. |
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| Keywords: | vitamin D thyroid thyroid-specific proteins CYP24A1 VDR rats |
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