AJP - Regulatory, Integrative and Comparative Physiology, Vol 244, Issue 6 823-R831, Copyright © 1983 by American Physiological Society
Factors that alter the plasma renin activity of the marmot
W. J. Ray and M. L. Zatzman
The effects of low doses of norepinephrine (NE) and furosemide and a volume
load (nonhibernators only) on plasma renin activity (PRA), mean arterial
pressure (MAP), heart rate (HR), left renal (RBF) and right iliac (IBF)
blood flow, cardiac index (CI), and total peripheral resistance (TPR) were
determined in euthermic and hibernating marmots. In nonhibernating marmots
NE produced an increase in CI and TPR and a decrease in RBF. In hibernators
this dose of NE caused an increase in MAP, HR, and renal resistance,
whereas it decreased PRA and did not alter iliac resistance. Furosemide
infusions led to an increase in PRA in both groups and an increase in TPR
in nonhibernators. The volume load in nonhibernators produced only a
decrease in PRA. A comparison of control data from the two groups indicated
that the renal and iliac beds contribute only a small portion to the
increase in TPR that occurs during hibernation.
