Action of Parathyroidectomy and Dihydrotachysterol on Myocardial Calcification Due to Coronary Vein Obstruction. ∗

Summary

Experiments in the rat indicate that ligature of the 2 main coronary veins induces inflammatory and degenerative changes in the subepicardial muscle layers followed by massive calcification. This type of myocardial calcification, unlike the onset of necrosis, is greatly enhanced by parathyroidectomy. The aggravating action of parathyroid deficiency is, however, counteracted by simultaneous removal of the thyroids. On the other hand, administration of dihydrotachysterol (DHT) actually prevents the myocardial calcification in intact, thyroidectomized, or parathyroidectomized rats. DHT merely influences the extent of calcification, not the cardiac necrosis itself. The changes recorded in serum calcium and inorganic phosphorus levels do not help explain the above findings.