gms | German Medical Science

Aim of the study was to to determine the importance of glomerular filtration for the regulation of cyclooxygenase-2 (COX-2) and of renin expression in the kidney cortex. Therefore the right ureters of male Sprague-Dawley rats were ligated for 5 weeks and hydronephrosis developed. While the cortex was still preserved a reduction of medullary mass was observed. Measurements of inulin clearance confirmed that glomerular filtration in the ligated kidney was abrogated. In animals kept under control conditions neither renocortical COX-2 nor renin gene mRNA abundance were different between the ligated and the intact kidney. Subcutaneous infusions of furosemide (12 mg/kg per day ) or treatment with low salt (0.02% w/w) in combination with the ACE-inhibitor ramipril (10 mg/kg per day) clearly stimulated the expression of COX-2 in the cortical thick ascending limbs of Henle and in the macula densa region as well as juxtaglomerular renin expression both in the intact and in the ligated kidneys.

We conclude that glomerular filtration is not essential for the regulation of COX-2 and of renin expression in the rat kidney cortex.