Intracerebroventricularly injected L-arginine-induced vasopressin release is mediated by cGMP in rats.
AIM
To study the possible role of cGMP in the effect of L-arginine-induced arginine-vasopressin (AVP) release.


METHODS
In anesthetized rats, saline, L-arginine, 8-Br-cGMP, L-arginine + methylene blue (an inhibitor of guanylyl cyclase) were injected intracerebroventricularly (icv) and the plasma vasopressin level was detected with radioimmunoassay.


RESULTS
Both 8-Br-cGMP 2.53 g.L-1 and L-arginine 100 g.L-1 increased plasma AVP level [from (2.6 +/- 0.3) to (6.6 +/- 0.4) ng.L-1, and from (3.2 +/- 0.5) to (5.8 +/- 1.4) ng.L-1, respectively; P < 0.01] 5 min after the icv injection; methylene blue (3.74 g.L-1) + L-arginine (100 g.L-1) did not change plasma AVP level.


CONCLUSION
cGMP was a mediator of the effect of L-arginine-induced AVP release.