Effects of tumor necrosis factor alpha on parathyroid hormone-induced increases in osteoblastic cell cyclic AMP

Tumor necrosis factor α (10^-10-10^-8M) had no effects on cyclic AMP production by the osteoblastic osteosarcomal cells, Saos-2 and G292, or normal rat calvarial cells. The cytokine did, however, inhibit the parathyroid hormone (PTH)-induced effect on cyclic AMP in the Saos-2 and normal rat osteoblastic cells. This inhibitory effect did not occur on prostaglandin E₂-induced cyclic AMP increases in the osteoblastic cells. Interleukin-1 (10 U/ml -100 U/ml) did not produce any effect on basal levels or PTH-induced cyclic AMP increases in these cells.