Angiotensin II as a trophic factor of white adipose tissue: stimulation of adipose cell formation.

White adipose tissue is known to contain the components of the renin-angiotensin system giving rise to angiotensin II (AngII). In vitro, prostacyclin is synthesized from arachidonic acid through the activity of cyclooxygenases 1 and 2 and is released from AngII-stimulated adipocytes. Prostacyclin, in turn, is able to favor adipocyte formation. Based upon in vivo and ex vivo experiments combined to immunocytochemical staining of glycerol-3-phosphate dehydrogenase (GPDH), an indicator of adipocyte formation, it is reported herein that AngII favors the appearance of GPDH-positive cells. In the presence of a cyclooxygenase inhibitor, this adipogenic effect is abolished, whereas that of (carba)prostacyclin, a stable analog of prostacyclin that bypasses this inhibition, appears unaltered. Taken together, these results are in favor of AngII acting as a trophic factor implicated locally in adipose tissue development. It is proposed that AngII enhances the formation of GPDH-expressing cells from preadipocytes in response to prostacyclin released from adipocytes.