Elevation of renin expression in strontium-treated wild-type mice. Two-month-old wild-type mice were fed the normal diet supplemented with 2.5% strontium chloride for 7 weeks before sacrifice. (a) Northern blot analysis of renin mRNA expression in the kidney from untreated and strontium-treated wild-type mice. Each lane represents an individual animal. (b) Quantitative results of the Northern analysis. (c) Blood ionized calcium concentration determined at the end of the treatment (n = 5 in each group). *P < 0.01 vs. untreated value (in b and c). NT, not treated; STR, strontium-treated.