Expression of renin-angiotensin system signalling compounds in maternal protein-restricted rats: effect on renal sodium excretion and blood pressure

Methods. The pregnancy dams were divided in two groups: with normal protein diet (pups named NP) (17% protein) or low protein diet (pups LP) (6% protein) during all pregnancy. Results. The present data confirm a significant enhancement in arterial pressure in the LP group. Furthermore, the study showed a significantly decreased expression of RAS pathway protein and Ang II receptors in the kidney and an increased expression in the adrenal of LP rats. The detailed immunohistochemical analysis of RAS signalling proteins in the kidney confirm the immunoblotting results for both groups. The present investigation also showed a pronounced decrease in fractional urinary sodium excretion in maternal protein-restricted offspring, compared with the NP age-matched group. This occurred despite unchanged creatinine clearance. Conclusions. The current data led us to hypothesize that foetal undernutrition could be associated with decreased kidney expression of AT(R) resulting in the inability of renal tubules to handle the hydro-electrolyte balance, consequently causing arterial hypertension.