Aim: This study investigates key components of the renin-angiotensin system (RAS) which play a central role in nephrogenesis and possibly in fetal programming of arterial hypertension in adult life.
Methods: We compared a genetic rat model with inborn nephron deficit, the Munich Wistar Fromter rat (MWF), to normotensive Wistar rats during nephrogenesis at day 19 of fetal development (E19) and at postnatal day 7 (D7).
Results: At E19 renal mRNA of angiotensin II type 1a (AT1a) (-50%, P<0.05) and type 1b (AT1b) (-55%, P<0.05) receptors were significantly decreased and renal mRNA expression of angiotensin II type 2 (AT2) receptor was fivefold increased in MWF (n=8) as compared to Wistar rats (n=8). At D7 renal mRNA expression of AT1a (-42%, P<0.05) remained lower in MWF (n=8) as compared to Wistar (n=7). Renal mRNA expression of AT2 (-30%, P>0.05) decreased in MWF (n=8) to about the level of the Wistar control (n=6).
Conclusions: Altered fetal expression of key molecules of the renin-angiotensin system in MWF indicates a possible role in genetic low nephron number hypertension.