Effects of Deflazacort and the L-6485 Metabolite on Epiphyseal Cartilage Carbohydrate Metabolism: Comparison with Prednisone

Summary

Male Sprague-Dawley rats were injected with 1 mg/100 g bw/day of prednisone, 1.25 mg/1-g bw/day of deflazacort, or its metabolite, for a period of 20 days. Epiphyseal cartilage slices were incubated in a modified Krebs Ringer bicarbonate buffer, at 37° C for 60 min, with either ¹⁴C-1- or ¹⁴C-6-glucose to quantitate both the absolute and relative rates of pentose shunt versus aerobic and anaerobic glycolytic activity, respectively. Measurements of both total and radioactive glucose uptake, lactate production and ¹⁴CO₂ generation were expressed as either umoles or DPM/mg cellular DNA/hr, respectively. This study demonstrated: (1) chronic prednisone administration decreased anaerobic glycolysis (glucose uptake and lactate production) 3-fold (P < 0.01); (2) prednisone on a chronic basis produced no measured alteration in either the pentose shunt or Kreb's cycle activity; (3) both deflazacort and the deflazacort metabolite significantly stimulated (P < 0.02) anaerobic glycolytic activity in epiphyseal cartilage tissue. In contrast to prednisone, the administration of either deflazacort or its L-6485 metabolite did not inhibit the glycolytic pathway of metabolism so necessary for epiphyseal cartilage growth and mineralization.

Key-Words:

Steroids - Cartilage - Intermediary Metabolism