Korean J Physiol Pharmacol.
1998 Dec;2(6):771-778.
Effects of angiotensin converting enzyme inhibition on gene expression
of the renin-angiotensin system in rats
- Affiliations
-
- 1Department of Physiology, School of Medicine, Kyungpook National University, Taegu 700-422, Korea.
Abstract
-
To investigate interaction of angiotensin converting enzyme (ACE)
inhibitor with local tissue renin-angiotensin system (RAS), changes in
gene expression of the RAS components in various tissues in response to
chronic administration of an ACE inhibitor, enalapril, were examined in
Sprague-Dawley male rats. Enalapril was administered in their drinking
water (3 ~ 4 mg/day) over 8 wk. Plasma and renal ACE activity
increased significantly after 4 and 8 wk of enalapril treatment. Renin
levels of the plasma and kidney of the enalapril-treated rats markedly
increased after 4 wk and decreased thereafter, but still remained
significantly higher than those of control rats. Kidney mRNA levels of
renin markedly increased after 4 and 8 wk of enalapril treatment, but
those of angiotensinogen and ANG II-receptor subtypes, AT1A and AT1B,
did not change significantly. The liver expressed genes for renin,
angiotensinogen and AT1A receptor subtype, but AT1B receptor subtype
mRNA was not detectable by RT-PCR. None of mRNA for these RAS
components in the liver changed significantly by enalapril treatment.
The hypothalamus showed mRNA expressions of renin, angiotensinogen,
AT1A and AT1B receptor subtypes. AT1A receptor subtype mRNA was more
abundant than AT1B receptor subtype in the hypothalamus as shown in the
kidney. However, gene expression of the RAS components remained
unchanged during 8-wk treatment of enalapril. In the present study,
chronic ACE inhibition increased plasma and renal levels of ACE and
renin, but did not affect mRNA levels of other RAS components such as
angiotensinogen, ANG II receptor subtypes in the kidney. Gene levels of
the RAS components in the liver and hypothalamus were not altered by
chronic treatment of enalapril. These results suggest the differential
expression of the RAS components in response to enalapril, and
localized action and some degree of tissue specificity of enalapril.