Effect of glucosamine-derived compounds on calcium ionophore-induced release of [3H]-proline-labeled articular collagen matrix. [3H]-proline-labeled monolayer of primary articular chondrocytes in 24-well plates was stimulated with calcium ionophore A23187 (15 μM) in the presence or absence of glucosamine hydrochloride (Glu) (25 mM), glucosamine sulfate (GS) (25 mM), N-acetyl glucosamine (N-A Glu) (25 mM), and N-acetyl mannosamine (N-A Mann) (25 mM). The 4-hour percentage release of labeled matrix collagen is shown. The results are presented as the mean of triplicate sets of wells ± standard error. A representative of three experiments is shown. *Statistically significant between cells stimulated with calcium ionophore and with Glu or GS. Ca Iono, calcium ionophore.