REGULATION OF ACYL COA SYNTHETASE EXPRESSION BY CYCLIC AMP DEPENDENT MECHANISM IN MA10 CELLS

CASTILLA ROCÍO; CANO FLORENCIA; MALOBERTI PAULA; CORNEJO MACIEL FABIANA; PAZ CRISTINA; PODESTA ERNESTO JORGE

Bariloche, Prov. of Río Negro, ARGENTINA

Congreso; XXXIX ANNUAL MEETING Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2003

We have previously described that an Acyl-CoA synthetase 4 (ACS4), an enzyme that has preference for Arachidonic Acid (AA) as substrate, and that an Acyl-CoA thioesterase (ARTISt) regulate in a concerted mode the intracellular levels of AA and steroid production. In this work we show that inhibition of steroidogenesis by the combined action of Triacsin C and Nordihydroguaiaretic acid, inhibitors of ACS4 and ARTISt respectively, was reverted by the addition of AA. The expression of both enzymes was analyzed by western-blot after treatment with cAMP in MA10 cells. ACS4 expression was increased while ARTISt expression remained unchanged. This increase correlates with the induction of StAR protein levels and steroid synthesis. The ACS4 increment was blocked in the presence of cycloheximide. These results suggest that the limiting step in the AA release necessary for the steroidogenesis involves the hormonal induction of ACS4.