Korean J Nephrol.  2002 Jan;21(1):29-38.

Expression of alphasmooth Muscle Actin, Aquaporin 1 and Renin after Blocking AT1 Receptor in Developing Renal Arterial System of Rat

• Lim JM
• Kim H
• Jung JY
• Lim SW
• Kim WY
• Han KH
• Cha JH
• Kim J

Abstract

BACKGROUND: Recent studies have demonstrated that renin, alphasmooth muscle actin(ASMA) and aquaporin-1(AQP1) participate in the development of renal arterial system. The components of the renin- angiotensin system have been shown to function as growth factors, apart from their classical roles in controlling blood volume and homeostasis. Interestingly, the vasoconstrictor angiotensin II(ANG II) appears to participate in the regulation of angiogenesis in various tissues. The present study examined the effect of ANG II type-1(AT1) receptor blocker losartan given during pregnancy or newborn rats on the expression of renin, ASMA and AQP1 in the developing renal arterial system.
METHODS
Pregnant and newborn rats received losartan(10 mg/kg/day) or saline for 4 and 8 days from E14 to parturition, and for 4 and 9 days starting at day 1 after birth, respectively. Kidneys of 17-day-old fetuses and 1-, 4-, and 9-day- old pups were processed for immunohistochemistry using antibodies to renin(1 : 10,000), ASMA(1 : 1,000), and AQP1(1 : 1,000).
RESULTS
In all pregnant groups, there were no differences in immunostaining for renin, ASMA, and AQP1 between losartan treated groups and saline treated groups. In all newborn groups, however, blockade of AT1 receptor with losartan found to increase expression of renin and ASMA but to have no effect on expression of AQP1 in the developing renal arterial system.
CONCLUSION
These results suggest that AQP1 expression is not associated with renin or ASMA expression during development of renal arterial system.

Keyword

Losartan; Renin; AQP1; alphasmooth muscle actin; Developing renal arterial system

MeSH Terms

Actins*
Angiotensins
Animals
Antibodies
Aquaporin 1*
Blood Volume
Fetus
Homeostasis
Humans
Immunohistochemistry
Infant, Newborn
Intercellular Signaling Peptides and Proteins
Kidney
Losartan
Parturition
Pregnancy
Rats*
Renin*
Actins
Angiotensins
Antibodies
Aquaporin 1
Intercellular Signaling Peptides and Proteins
Losartan
Renin