Hypertension, Vol 21, 654-659, Copyright © 1993 by American Heart Association
I Antonipillai
Epidermal growth factor (EGF) is not only a cell mitogen but a potent
vasoconstrictor that shares many properties with angiotensin II. Because
EGF is localized in the kidney, we have studied the direct effects of EGF
on renin secretion using both static incubations and perifusions of rat
renal cortical slices. EGF at 5 x 10(-9) M significantly inhibited renin
secretion in static incubations (control, 100 +/- 3%; EGF, 72 +/- 3%; p
< 0.001). When added to perifusions, EGF acted rapidly, reducing renin
secretion at the earliest time period (10 minutes). Similarly, transforming
growth factor-alpha, which can bind to the EGF receptor, also inhibited
renin secretion (control, 92 +/- 8%; transforming growth factor-alpha [2 x
10(-9) M], 63 +/- 4%; p < 0.02). Because both prostaglandins and
lipoxygenase products of arachidonic acid have been shown to play a role in
some EGF-mediated actions, we examined these possible mechanisms of EGF
action. Meclofenamate, a cyclooxygenase blocker, and BW755c and baicalein,
both lipoxygenase blockers, were studied. None of these agents altered EGF-
mediated renin inhibition. EGF action has also been coupled to the
stimulation of tyrosine kinase activity; therefore, we examined the effects
of the tyrosine kinase inhibitors genistein and quercetin. Both genistein
(10(-5) M) and quercetin (10(-5) M) abolished the inhibition of renin by
EGF (control, 100 +/- 3%; EGF, 82 +/- 4%; EGF plus genistein, 110 +/- 7%; p
< 0.01; EGF, 75 +/- 4%; EGF plus quercetin, 92 +/- 4%; p <
0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
ARTICLES
Epidermal growth factor is a potent inhibitor of renin secretion
USC Medical Center, Division of Endocrinology, Los Angeles 90033.
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