Calcium content of serum and myocardium in vitamin D-induced cardionecrosis

The dynamics of calcium content alterations in serum and heart muscle in relation to vitamin D-induced cardionecrosis was the aim of the experiment performed on female Wistar rats killed at different times after one or two intraoral doses of 100,000 IU of vitamin D. Calcium concentration in the serum showed great individual variability, although the mean value was significantly elevated after 22 h following one dose and after 2 h following two doses of vitamin D. In the heart muscle the mean calcium content increased 72 h after one dose and 24 h after two doses of 100,000 IU of calciol, but in individual rats the increase of Ca concentration was observed as early as 30 h after one dose, in some it was normal even after 144 h of two doses and varied between individual rats 20-30-fold. The degree of cardionecrosis showed great variability among rats treated with the same dose of calciol and at the same phase of the experiment. Cardionecrosis was always preceded by great accumulation of calcium in the heart muscle and its extent was in direct correlation to the amount of calcium in the tissue, regardless of the dose of calciol and phase of the experiment.