The in vitro production of prostanoids by cultured bovine articular chondrocytes.

Bovine articular chondrocytes, cultured as cell suspensions and monolayers, produced prostaglandin (PG) E2 and PGI2 (assayed as 6 keto PGF1 alpha), rather less PGF2 alpha and irregular quantities of thromboxane (Tx) B2. Addition of foetal calf serum to the medium greatly stimulated PG production (a sixfold increase in PGE2 and a twofold increase in 6 keto PGF1 alpha). Prostanoid production by cell suspensions grown in serum-free medium generally plateaued after 24 hours. In the presence of 20% foetal calf serum, prostanoid production in long-term monolayer cultures increased during the first 6 days of culture. Levels of PGE2 and TxB2 then decreased, while 6 keto PGF1 alpha levels remained high. Indomethacin (10(-6)M) inhibited chondrocyte PG production both in the presence and absence of added arachidonic acid (10(-4)M). Prostanoids produced by chondrocytes may play a role in the modulation of cartilage metabolism in vivo.