Unilateral reteral obstruction(UUO) in early develjopment impairs renal growth. To investigate the potential role of growth-related peptides in this response. Sprague-Dawley rats underwent later. Renal mRNA was quantitated by Northern and dot
blot
with
complementary DNA probes for renin and transforming growth factor beta 1(TGF-β1). Renin distribution was determined by immunohistomchemisry. Adult rats were also studied 3 or 14 days after UUO or sham operation. Unlike the the neonate, in which
renal
DNA failed to increase with chronic ipsilateral UUO, renal DNA increased in the adult. UUO increased renal renin mRNA and protein distributin in the neonate, but mRNA expression did not change in the adult. TGF-β1 expression increased in the
obstructied kidney in both neonates and adults. Since renal renin expression is increased by UUO, it was hypothesized that by activation of angiotensin Ii type 1 receptor, angiotensin II regultes expression of TGF-β1 in the obstructed idney.
Sprague-Dawley rats underwent left UUO or sham operation within the first 48 hours of life, and received losartan or saline, After 14 days, stead-state renal mRNA was determined for renin and TGF-β1. Losartan reduced the DNA content of the
intact
kidneys, but did not further decrease that of the obstncted kindey. Losartan increased renal renin renin expression regardless of UUO. In contrast, losartan reduced TGF-β1 expresson by 34% in obstructed kidneys, but did not affect TGF-β1 in
intact
kidneys.
In conclusion, neonatal UUO delays renal maturation, possibly related to altered renin and TGF-β1 expression and actvation of the angiotensin II type 1 receptor is necessary for normal renal growth, and TGF-β1 is regulatedd by angiotensin II
type
1
receptor in the obstructed, but not intact kidneys.
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