Effects of glucocorticoid on adipocyte size in human bone marrow.

The pathogenesis of corticosteroid-induced femoral head necrosis is assumed to be related to lipid metabolism. Mature fat cells are believed to play a central role in lipid metabolism. The purpose of this study was to investigate the size of mature fat cells in the human femoral head after steroid treatment. Cancerous bone tissue was obtained from the femoral heads of 20 women who had undergone total hip arthroplasty. This bone tissue was subsequently incubated in a medium containing 10(-7) or 10(-5) M dexamethasone for 5 days. Mature fat cells from the bone marrow were observed by scanning electron microscopy, and the largest diameter of individual fat cells was measured. The size of the mature fat cells in human bone marrow increased after high-dose steroid treatment. The largest fat cell volume after steroid treatment was one and one-half times larger than that observed in the control. Steroid-induced osteonecrosis is known to sometimes occur after high-dose steroid treatment. These findings may indicate the pathogenetic factors in the early stage of steroid-induced osteonecrosis.