The ultrastructural effect of estrogens on bone cells in thyroparathyroidectomized rats.
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| Abstract |
To determine the direct effect of estrogen on bone cells, female rats were thyroparathyroidectomized and given either 200 microng of estradiol cypionate or placebo treatment for 4 to 30 days. After 8 days, an osteosclerosis of the tibial metaphysis developed in rats treated with estrogens. Osteoblasts in estrogen-treated rats were interpreted ultrastructurally to be less active in bone formation than controls. Osteocytes in estrogen-treated rats were inactive compared to osteocytes in control rats which were continuing the process of bone formation. Osteoclasts were decreased in numbers in rats treated with estrogen; however, the electron microscopic characteristics of osteoclasts did not differ from controls. These cellular changes were associated with a severe hypocalcemia in both estrogen-treated and control rats. Serum phosphorus and urinary hydroxyproline were lowered significantly by the administration of estrogen. It is concluded that metaphyseal osteosclerosis develops in estrogen-treated rats independent of parathyroid hormone and calcitonin. The osteoclerosis is due to an effect of estrogens to reduce osteoclast-numbers and a lesser inhibitory effect on the bone-forming activity of osteoblasts and osteocytes. (Am J Pathol 87:311-322, 1977).
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| Authors | S E Weisbrode, C C Capen |
| Journal | The American journal of pathology (Am J Pathol) Vol. 87 Issue 2 Pg. 311-22 (May 1977) ISSN: 0002-9440 [Print] United States |
| PMID | 851169 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.) |
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