The renin-angiotensin-aldosterone system and the prostaglandins (PG) are important determinants in the regulation of blood pressure and salt and water balance. Angiotensin II (AII), by contracting vascular smooth muscle and stimulating aldosterone and PG synthesis, occupies a central role, in these control mechanisms. Recently, two other angiotensins, (des-Asp1) AI and (des-Asp1) AII, were found to have actions qualitatively similar to AII. In view of these findings vascular adrenal roles of these peptides require further characterization in states of altered sodium balance, potassium balance, and experimental hyperaldosteronism. AII has been found to stimulate synthesis in many tissues; however, its action on intra-adrenal PG synthesis has been neglected. This possibility may be important since PGE stimulates aldosterone biosynthesis as well as augmenting AII-induced aldosterone biosynthesis. Thus, intra-adrenal prostaglandins may mediate a component of the basal and AII-mediated steroidogenesis. This research proposal will characterize in vivo and in vitro the vascular and adrenal actions of AI, AII, and their des-aspartyl metabolites in states of normal and altered sodium and potassim balance and experimental hyperaldosteronism. Secondly, the intra-adrenal role of PG's and their interactions with the angiotensins in the control of steroidogenesis will be determined in normal and altered states of sodium and potassium balance. Finally, the site of angiotensin and PG stimulation of aldosterone biosynthesis will be determined. By furthering our understanding of these normal control mechanisms, we hope to better understand the involvement of these two hormonal systems in hypertensive and edematous conditions.