AJP - Renal Physiology, Vol 253, Issue 3 471-F475, Copyright © 1987 by American Physiological Society
Temperature sensitivity of renin-angiotensin system in the ground squirrel
C. T. Harker, M. J. Kluger and R. L. Malvin
The alteration of renin release by alpha- and beta-adrenoceptors located on
the juxtaglomerular cells has been shown to be temperature sensitive in
nonhibernating mammals. These experiments investigate the effects of
temperature on renin secretion by cortical slices of kidneys from the
thirteen-lined ground squirrel Spermophilus tridecemlineatus. At 37 degrees
C, beta-stimulation (isoproterenol 10(-7) M) increased the release of renin
by slices taken from nonhibernating ground squirrels but had no effect on
those taken from hibernating squirrels. The alpha-agonist phenylephrine
(10(-5) M) had no effect on slices from nonhibernating squirrels but
enhanced the release rate in those from hibernating ground squirrels,
providing the first evidence of in vitro stimulation of renin release by an
alpha-agonist. When incubated at 11 degrees C, kidney slices from both
hibernating and nonhibernating animals were unresponsive to both alpha- and
beta-agonists until incubation times were doubled. Under these prolonged
conditions, phenylephrine again stimulated renin release. These results
indicate that both in vitro and in vivo cooling alter the responses of
alpha- and beta-adrenoceptors to renin-releasing stimuli.
