[The vitamin D endocrine system and bone tissue mineral metabolism in rats with adjuvant arthritis: the effect of 1,25-dihydroxyvitamin D3].

Adjuvant arthritis was induced in male rats by injecting bacillus Calmette-Guèrin in mineral oil in a hindpaw. A decrease in bone density, calcium and phosphorus content due to polyarthritis was found in the tibia of the noninjected hind leg. Arthritic rats demonstrated serum 1,25-dihydroxyvitamin D deficiency along with constant level of 25-hydroxyvitamin D. The disease caused a significant expression of 1,25-dihydroxyvitamin D3 receptors in lymphocytes. Arthritic rats were treated with 1,25-dihydroxyvitamin D3 (0.15 mg/kg/day orally) for 35 days. The treatment prevented the development of osteoporosis and a decrease of 1,25-dihydroxyvitamin D levels as well as reduced the expression of 1,25-dihydroxyvitamin D receptors in lymphocytes.