To determine whether high protein feeding throughout development affects renal growth, renal hemodynamics, and the intrarenal distribution of renin and its mRNA in the adult animal, male Wistar rats were fed diets containing either 20% protein [normal (NP), n = 12] or 40% protein [high (HP), n = 12] from weaning until studied at 6 or 12 wk of age. Kidney weight, kidney weight-to-body weight ratio, cortical DNA content, and cortical protein-to-DNA ratio were higher in HP- than in NP-fed rats at 6 and 12 wk of age. Somatic and kidney growth response to HP was blunted by angiotensin II type 1 receptor antagonist Dup 753. Glomerular filtration rate and renal plasma flow were higher in HP- than in NP-fed rats at 6 and 12 wk of age. The intrarenal distribution of renin and renin mRNA, assessed by immunocytochemistry and in situ hybridization, respectively, were markedly different between the two groups. In NP-fed rats, renin and renin mRNA were confined to a juxtaglomerular location. In HP-fed rats, renin and its mRNA extended proximally along the afferent arterioles. The percentage of visible afferent arteriolar length containing renin or renin mRNA was higher in HP-fed rats (60 +/- 3.2 and 61 +/- 3.9%, respectively) than in NP-fed rats (39 +/- 2.5 and 33 +/- 0.6%; P less than 0.05). Also, the percentage of juxtaglomerular apparatuses (JGAs) containing renin or renin mRNA was higher in HP-fed rats (80 +/- 1.6 and 72 +/- 2%, respectively), than in NP-fed rats (46 +/- 2.2 and 40 +/- 4%; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)