Use of 3H-glucosamine and 35S-sulfate with cultured human chondrocytes to determine the effect of glucosamine concentration on formation of chondroitin sulfate.

Objective: To determine whether addition of glucosamine will stimulate synthesis of chondroitin sulfate by cultures of human chondrocytes, and to compare the relative contribution of endogenous glucosamine to exogenous glucosamine in forming chondroitin sulfate.

Methods: Cultured human chondrocytes were incubated with (35)S-sulfate and various amounts of glucosamine to determine whether any incremental formation of chondroitin (35)S-sulfate occurred. Similarly, chondrocytes incubated with variable concentrations of (3)H-glucosamine were examined to determine how much the incorporation into (3)H-chondroitin sulfate was diluted by provision of endogenous glucosamine that was derived by metabolism from glucose.

Effects of [3H]glucosamine concentration on [3H]chondroitin sulphate formation by cultured chondrocytes.

GlcN (glucosamine) is now promoted over the counter for implied treatment of osteoarthritis, ostensibly by stimulating biosynthesis of cartilage chondroitin sulphate. In order to evaluate whether exogenous GlcN has any stimulatory effect, we have incubated mouse chondrocytes with [(35)S]sulphate and various amounts of GlcN, to determine whether any increment in chondroitin [(35)S]sulphate formation occurs. Similarly we have used varying concentrations of [(3)H]GlcN to determine the dilution of incorporation into [(3)H]chondroitin sulphate due to provision of endogenous GlcN by metabolism from glucose at two different glucose concentrations.