Glycosaminoglycan synthesis and glucose uptake by rheumatoid and nonrheumatoid fibroblastic cells in culture. The effect of nutritional factors.

Glycosaminoglycan (GAG) synthesis and glucose uptake by rheumatoid (R) and nonrheumatoid (NR) synovial cells were studied at the second subculture during four different sets of nutritional conditions and at sequential, defined intervals of the growth cycle. Synovial fibroblastic cells in monolayer cultures secrete both hyaluronic acid and sulfated GAGs in a ratio of about 8 : 1. With increasing cell density the ability to sulfate GAGs appears to decrease. No significant differences in GAG synthesis between rheumatoid and nonrheumatoid lines on a per cell basis could be detected during any interval in the growth cycle. Similarly, no significant differences of glucose uptake per cell could be demonstrated between rheumatoid and nonrheumatoid lines under the various protocols applied throughout the growth cycle. The most important factor determining glucose uptake per cell is the availability of glucose in the medium which is in turn closely correlated with cell number.