Alpharadiographic and histological observations on the skeletal effects of hypervitaminoses A and D in the rat.

Abstract

AbstractMale Holtzman rats were fed large doses of vitamin A, D or A and D for 43 days. Sections of the tibia demineralized in EDTA were submitted to alpharadiography or stained by a variety of procedures, including mucopolysaccharide histochemistry. The results were as follows: In hypervitaminosis D, slightly increased periosteal apposition of normal bone; greatly increased maturation of osteocytes with lacunar enlargement and confluence, interstitial metachromasia and loss of density (osteocytic osteolysis). In hypervitaminosis A, large growth of abnormally stained cancellous bone at periosteum and stimulation of osteolysis in new and old bone. In combined A and D hypervitaminoses, the peripheral apposition rate exceeded that induced by vitamin A or vitamin D alone. The new bone appeared fragile and this combined with increased osteolysis was responsible for a number of spontaneous fractures.