AJP - Heart and Circulatory Physiology, Vol 243, Issue 4 584-H589, Copyright © 1982 by American Physiological Society
Effects of prostacyclin on hepatic vasculature and metabolism of renin in conscious dogs
S. F. Echtenkamp, J. O. Davis, R. H. Freeman, J. R. Dietz and D. Villarreal
Prostaglandins have been implicated as important regulators of vascular
resistance during high-renin states, and they act as potent stimuli for
renin release. This study examines the effects of prostacyclin (PGI2) in
conscious sodium-replete and -deplete dogs on the hepatic vasculature and
on hepatic function and their role in determining the level of arterial
plasma renin activity (PRA). Concurrent measurements of kidney function
were made for comparison. Conscious trained dogs with chronic indwelling
catheters were given intravenous infusions of PGI2. With a low dose of PGI2
(2 x 10(-8) g . kg-1 . min-1) hepatic blood flow increased while splanchnic
vascular resistance fell. With a higher dose (8 x 10(-8) g . kg-1 . min-1)
mean arterial pressure fell, and both hepatic and renal blood flow
increased while splanchnic and renal resistances fell. The PGI2 infusion
was accompanied by an increase in PRA. In both sodium-replete and -deplete
animals the increases in PRA were accompanied by proportional increases in
the hepatic extraction of renin and increases in the hepatic clearance of
renin. Small but significant differences were found in the responses of
sodium-replete and -deplete animals to PGI2 infusion. These results
demonstrate that PGI2 has a potent influence on both the splanchnic and
renal vasculatures and the hepatic clearance of renin and thus the role of
the liver in determining hyperreninemia.
