Potassium control of extrarenal renin secretion in transgenic (mRen-2)27 and normal rats

Plasma active renin and prorenin were followed for 12 h after bilateral, un ilateral, and sham nephrectomy (BNx, UNx, and SNx) in anesthetized transgen ic (mRen-2)27 rats to compare them with Sprague-Dawley and spontaneously hy pertensive rats (SDR and SHR). In Ren-2 rats, active renin and prorenin inc reased with plasma potassium post-BNx and were augmented by potassium infus ion. The increase in prorenin but not active renin was abolished by bilater al adrenalectomy (BADRx). However, this did not reduce prorenin below norma l, indicating that the high plasma prorenin Ren-2 phenotype is not only of adrenal origin. SNx and UNx also raised plasma active renin and prorenin in Ren-2 rats, with positive correlations to plasma potassium. In SDR and SHR , active renin fell below prorenin post-BNx, and adrenal ablation and potas sium loading tin SDR) modified the decreasing active renin profile consiste nt with low levels of regulated extrarenal secretion. In Ren-2 rats, adrena l but not extra-adrenal prorenin secretion is potassium sensitive and stres s related. The unidentified source of active renin in BNx+BADRx Ren-2 rats is also potassium and stress related.