STIMULATION OF CORTISOL PRODUCTION THROUGH ANGIOTENSIN AT(2) RECEPTORS IN BOVINE FASCICULATA CELLS

Bovine fasciculata cells in culture (BAG) express both AT(1) and AT(2) angiotensin receptors. The role and signaling pathways of this latter receptor are still the subject of debate. We found that in BAC stimulation of cortisol (F) production by angiotensin II (A II) is accounted for by both receptor subtypes. We have investigated the potential AT(2) signalling pathways involved in this response. As previously described in other cells, we found this receptor to mediate inhibition of ANP stimulated cGMP production through a phosphodiesterase independent pathway. This phenomenon does however not appear to be involved in cortisol production as this response was not affected by the addition of 8-Br-cGMP or ANP. It was however abolished after down-regulation of PKC by phorbol esters, but not by G(i) inhibition with pertussis toxin. Moreover and as opposed to the AT(1) mediated response, AT(2) receptor stimulation potentiated K+ induced F production. In conclusion, these observations suggest that the AT(2) pathway, which mediates F production requires intact PKC and might involve a G(i) independent stimulation of Ca++ or K+ channels.