Synergistic action of angiotensin II on norepinephrine-induced prostaglandin release from rat glomeruli.

The effects of vasoactive substances on the release of prostaglandin (PG) and thromboxane (TX) from isolated rat glomeruli were investigated. The PGE2, PGF2 alpha, 6-keto-PGF1 alpha, and TXB2 release during 60 min into Krebs-Henseleit medium was assessed by radioimmunoassay following extraction. Norepinephrine (NE) stimulated PGE2 (from 2,117 +/- 117 to 3,968 +/- 182 pg X mg protein-1 X 60 min-1, P less than 0.01) at a concentration of 10(-4)M and PGF2 alpha (from 2,748 +/- 285 to 8,535 +/- 495 pg X mg protein-1 X 60 min-1, P less than 0.01) at a concentration of 10(-5)M. However, neither angiotensin II (ANG II) nor arginine vasopressin (AVP) affected the release of PG and TXB2 at concentrations up to 10(-5)M. In the presence of 10(-5) M NE, ANG II enhanced the release of PGE2 (from 3,307 +/- 207 to 6,865 +/- 469 pg X mg protein-1 X 60 min-1., P less than 0.01) and PGF2 alpha (from 3,652 +/- 252 to 6,612 +/- 388 pg X mg protein-1 X 60 min-1, P less than 0.01) at a concentration of 10(-8)M, whereas AVP lacked any similar effect. These results indicate that catecholamine acts as a major stimulant for the release of PG from isolated glomeruli via alpha-receptors. ANG II may work in cooperation with catecholamine, but AVP appears to play little role.