[Clinical signs and changes in serum and tissue chemistry in rats treated with vitamin D3 (calciferol)]

In the present work the effect of subcutaneous administration of 250, 500 and 750 microg (10.000, 20.000 and 30.000 IU, respectively) of vitamin D3 (calciferol) daily for eight days, on serum concentrations of vitamin D3 and 25-hydroxyvitamin D3 (25-OH-D3) and on serum and tissue concentrations of Ca, Zn, Cu and Fe in 45 white male Wistar rats, aged 12 weeks and weighing 180-200 g, have been studied. The group control was integrated by 15 healthy rats with similar characteristics (strain, gender, age and weight) that treated animals. Administration of high doses of calciferol produced a hypervitaminosis D characterized by a significant (p < 0.05) increase in serum vitamin D3 and 25-OH-D3, diverse clinical signs (such as, anorexia, marked loss of body weight, bloody diarrhea, bilateral conjunctivitis, and death), hypercalcemia, hypozincaemia, hypercupremia, hypoferraemia and an alteration in the tissue distribution of Ca, Zn, Cu and Fe as compared with untreated controls. Hypercalcemia and inflammation are prominent findings in hypervitaminosis D. Inflammation or infection induce systemic changes, collectively known as the acute phase response. Among the varied alterations that together produce this response are hypoferraemia, hypozincaemia and hypercupremia. It is likely that these responses are mediated, in part, by production and release of cytokines such as interleukin 1, interferons (IFN-alpha), interleukin 6 (11-6) and tumor necrosis factor (TNF). The development of hypoferraemia during inflammation requires hepcidin, an iron regulatory hormone, a disulfide-rich peptide, produced in the liver in response to the release of I1-6 during inflammation/infection. In conclusion, our results provide evidence that short-term administration of high doses of vitamin D determined diverse clinical signs and produced a marked increase of serum vitamin D3 and 25-OH-D3 and a marked alteration in the serum and tissue concentrations of Ca, Zn, Cu, and Fe. These changes depend on the doses given of vitamin D.