The complement membrane attack complex stimulates the prostanoid production of cultured glomerular epithelial cells.

Incubation of cultured rat glomerular epithelial cells (GEC) with sublytic amounts of the purified complement components C5b6, C7, C8 and C9 greatly stimulated the release of the prostanoids prostaglandin E (PGE) and thromboxane B2. Incubation of GEC with C5b-8 was also stimulatory, whereas omission of C7 abolished the enhanced prostanoid production. These effects were dose-dependent. The increased release of PGE was biphasic with peaks at 5 min and 24 h of incubation. The second peak could be prevented by treatment with cycloheximide, suggesting its dependence on protein synthesis. The observations on cultured GEC provide evidence that terminal complement components alter the metabolism of glomerular cells, resulting in increased production of prostanoids. The results are consistent with the concept that deposition of nonlytic amounts of complement in the glomerular capillary wall may affect the GEC in vivo and may indirectly contribute to abnormalities of the glomerular filter as it is seen in glomerular disease.