Renal prostaglandin E₂ biosynthesis: Dependence on angiotensin II

To study the interaction of the prohypertensive renin-angiotensin axis with the antihypertensive renal prostaglandins, angiotensin-converting enzyme inhibition (captopril and teprotide) and angiotensin blockade (Sar¹-lle⁸-All) were produced in rabbits in vivo and renal slice prostaglandin E₂ was measured in vitro after 30 minutes of incubation in Krebs-Ringer HCO^-₃ buffer. In rabbits with angiotensin-converting enzyme inhibition, de novo prostaglandin E₂ synthesis decreased in cortical, outer medullary and papillary slices by 85, 52 and 47 percent, respectively. Similar degrees of inhibition were observed with angiotensin blockade. It is concluded that renal prostaglandin E₂ synthesis is angiotensin II dependent under these conditions. This finding suggests that any increase in the prohypertensive antinatriuretic renin-angiotensin axis may be associated with a secondary increase in renal prostaglandin E₂ which may be acting in an antihypertensive natriuretic compensatory fashion.