Induction of adrenomedullin by hypoxia and cobalt chloride in human colorectal carcinoma cells.

Adrenomedullin (ADM) is a vasodilator peptide, first isolated from human pheochromocytoma. To explore the pathophysiological role of ADM in ischemic conditions, we investigated the effects of hypoxia on ADM production and ADM mRNA expression in a cultured human colorectal carcinoma cell line, DLD-1. Northern blot analysis and radioimmunoassay showed that hypoxia stimulated the accumulation of ADM mRNA in the DLD-1 cells and immunoreactive ADM (ir-ADM) in the cultured media. Exposure to hypoxia for 12 hours increased ADM mRNA levels about 6-fold and ir-ADM levels about 4-fold. Moreover, treatment of DLD-1 cells with cobalt chloride, which mimics hypoxic states, significantly increased ADM mRNA levels about 18-fold and ir-ADM levels about 4-fold. These results suggest that ADM plays an important role in the pathophysiology of ischemic states.