Endotoxic lipopolysaccharides stimulate steroidogenesis and adenylate cyclase in adrenal tumor cells

Lipopolysaccharides (endotoxins) from Escherichia coli, Serratia marcesens and Salmonella typhosa stimulated steroid production in Y-1 adrenal tumor cells in culture with a latent period of 3-4 h. Lipid A, derived from Escherichia coli lipopolysaccharide, also stimulated steroidogenesis. Lipopolysaccharides and lipid A also stimulate adenylate cyclase activity and cause rounding of the cells. In contrast, lipopolysaccharides do not stimulate steroidogenesis in receptor-deficient adrenal tumor cells (OS-3) or Leydig tumor cells (I-10). This tends to rule out contamination by enterotoxin to which these lines respond. Although both hormone and lipopolysaccharide responses are lost in these lines, there was no interaction between these sites as judged by the failure of lipopolysaccharides to block, during their latency, the response to corticotropin in Y-1 cells. The possibility that the lipopolysaccharide effect is one on membrane conformation is discussed.