Glucocorticoid-induced changes in the activity of cartilage alkaline phosphatase.

Glucocorticoid hormones are known to exert distinct inhibitory effects upon cartilage metabolism and endochondral bone growth. This study examined the influence of triamcinolone hexacetonide, a long-acting synthetic analogue off cortisol, on the activity of non-specific alkaline phosphatase i condylar cartilage of neonatal mice. Four-day-old mice received a single dose (10 mg/kg) of the hormone and the activity of beta-glycerophosphatase was assayed 3 and 6 days thereafter. Whereas no significant changes were noted in the enzyme's specific activity, distinct alterations were observed in the latter's distributional pattern. By 48 hours cells along both the proliferative and chondroblastic zones exhibited a significant enhancement of alkaline phosphatase activity. This increase in enzyme activity was most prominent along the cells' plasmalemma and within their adjacent matrix. Thus, glucocorticoid hormones possess a significant stimulatory effect upon alkaline phosphatase activity in very young cartilage cells which in turn might affect the mineralization process.