Effect of cortisone on collagenolytic activity in the rat

Bone changes during prednisone treatment

To evaluate changes inbone composition during treatment with corticosteroids, the bone mineral content (BMC, measured by photon absorptiometry) and the degree of bone mineralization (measured as the bone phosphorus/hydroxyproline ratio) were determined in 18 patients during prednisone treatment for haematological and connective tissue diseases. The prednisone dose ranged from 12 to 51 mg/day (mean 27). The BMC decreased significantly (mean 2.5%) during the studied 12 weeks of treatment, but the change did not correlate significantly to the prednisone dose. The degree of bone mineralization remained unchanged, indicating equal losses of mineral and of collagen in bone during prednisone treatment. The changes correspond to a rapidly developing oesteoporotic state.

Zonal analysis of cytoplasmic steroid hormone receptor levels: replication and synthetic activity in embryonic calf growth cartilage

Using the dextran charcoal method, a specific steroid receptor for dexamethasone, but not 17 beta-estradiol or 17 alpha-methyltrienolone, was demonstrated in cytosol prepared from mid-gestation fetal calf growth cartilage. Zonal analysis of cytoplasmic receptor levels showed that tissue sections from the center, the peripheral surface, and the palisade section bound 229 +/- 111, 173 +/- 64, and 15 +/- 28 femtomole dexamethasone per mg of protein, respectively. Incorporation of 3H-thymidine, 35S-sulfate, and 3H-proline into cartilaginous tissues was used as an index of replication and synthetic activity. The percentage of 3H-thymidine labeled nuclei, as determined by radioautography, showed that the palisade zone has a significantly lower replicating activity (P less than 0.001). Values were 5.6 +/- 1.2, 5.4 +/- 1.2, 3.8 +/- 1.3, and 1.1 +/- 0.2 for the center, peripheral surface, and upper and lower half of the palisade section. The rate of sulfate and proline incorporation into the palisade zone was over seven times higher than the central and peripheral surface (P less than 0.001). The difference in the rate of matrix synthesis and proliferating activity in these regions may be related to the zonal heterogeneity of receptor levels of glucocorticoids in fetal growth cartilage.