Enzyme activities of synovial fibroblast samples of rheumatoid arthritis and osteoarthritis patients after TGF-β1 treatment. Synovial fibroblasts (SFs) from patients with rheumatoid arthritis (RA) (n = 6) or osteoarthritis (OA) (n = 6) were cultured in the presence or absence of tumor growth factor beta 1 (TGF) for 24 hours. β-D-N-acetyl-glucosaminidase (NAG) and β-D-glucuronidase (GusB) activities were determined in cell lysates and the corresponding supernatants (S/N): (a) NAG in cell lysate, (b) NAG in supernatant, (c) GusB in cell lysate and (d) GusB in supernatant. Most NAG activity was found inside the SFs, while GusB was predominantly secreted into the supernatant. Data shown as mean ± standard error mean. P < 0.01 ***.