Prostaglandin endoperoxide H synthase expression in human thyroid epithelial cells

KAT-50, an established human thyrocyte cell line, expresses constitutively high levels of prostaglandin endoperoxide H synthase-2 (PGHS-2), the inflam matory cyclooxygenase. Here, we examine primary human thyrocytes. We find t hat they, too, express PGHS-2 mRNA and protein under control culture condit ions. A substantial fraction of the basal prostaglandin E-2 (PGE(2)) produc ed by these cells can be inhibited by SC-58125 (5 muM), a PGHS-2-selective inhibitor. Interleukin (IL)-1 beta (10 ng/ml) induces PGHS-2 expression and PGE(2) production in primary thyrocytes. The induction of PGHS-2 and PGE(2 ) synthesis by IL-1 beta could be blocked by glucocorticoid treatment. Unli ke KAT-50, most of the culture strains also express PGHS-1 protein. Our obs ervations suggest that both cyclooxygenase isoforms may have functional rol es in primary human thyroid epithelial cells, and PGHS-2 might predominate under basal and cytokine-activated culture conditions.