| Abstract: | ![]()
The synthetic heparin substitute dextran sulphate induces osteoporosis after prolonged administration to experimental animals. The possibility that this is brought about indirectly by hypocalcaemia and secondary hyperparathyroidism as a result of the binding of ionised calcium by dextran sulphate has been studied in rats.Twenty-four rats were given 25 mg. per kg. per day of sodium dextran sulphate for periods up to 11 weeks. Sixteen were given the same amount of dextran sulphate but were previously parathyroidectomised. Two control groups comprised 17 intact and 15 parathyroidectomised rats, respectively. The limb bones were examined histologically and their sizes and growth rates measured from radiographs and by tetracycline labelling. The parathyroid glands from intact control and dextran sulphate treated rats were compared histologically and the serum calcium estimated in each animal.All rats given dextran sulphate showed thinning of the metaphyseal cortical bone as a result of impaired endochondral ossification. Parathyroidectomised rats continued to grow and the lengths of their limb bones were unaffected. Parathyroidectomy had no influence on the occurrence or severity of bone changes attributed to dextran sulphate. Furthermore, serum calcium remained normal and there was no evidence of parathyroid hyperplasia in the intact dextran sulphate treated rats.It is concluded that dextran sulphate induces osteoporosis in growing animals by interfering with endochondral ossification and does not induce hypocalcaemia and secondary hyperparathyroidism. |
