Nishimoto M, Fujita T. Renal mechanisms of salt-sensitive hypertension: contribution of two steroid receptor-associated pathways. Am J Physiol Renal Physiol 308: F377-F387, 2015. First published December 17, 2014 doi:10.1152/ajprenal.00477.2013.-Although salt is a major environmental factor in the development of hypertension, the degree of salt sensitivity varies widely among individuals. The mechanisms responsible for this variation remain to be elucidated. Recent studies have revealed the involvement of two important signaling pathways in renal tubules that play key roles in electrolyte balance and the maintenance of normal blood pressure: the  2-adrenergic stimulant-glucocorticoid receptor (GR)-with-no-lysine kinase (WNK)4-Na ϩ -Cl Ϫ cotransporter pathway, which is active in distal convoluted tubule (DCT)1, and the Ras-related C3 botulinum toxin substrate (Rac)1-mineralocorticoid receptor (MR) pathway, which is active in DCT2, connecting tubules, and collecting ducts.  2-Adrenergic stimulation due to increased renal sympathetic activity in obesity-and salt-induced hypertension suppresses histone deacetylase 8 activity via cAMP/PKA signaling, increasing the accessibility of GRs to the negative GR response element in the WNK4 promoter. This results in the suppression of WNK4 transcription followed by the activation of Na ϩ -Cl Ϫ cotransporters in the DCT and elevated Na ϩ retention and blood pressure upon salt loading. Rac1 activates MRs, even in the absence of ligand binding, with this activity increased in the presence of ligand. In salt-sensitive animals, Rac1 activation due to salt loading activates MRs in DCT2, connecting tubules, and collecting ducts. Thus, GRs and MRs are independently involved in two pathways responsible for renal Na ϩ handling and salt-sensitive hypertension. These findings suggest novel therapeutic targets and may lead to the development of diagnostic tools to determine salt sensitivity in hypertensive patients.salt-sensitive hypertension; mineralocorticoid receptor; glucocorticoid receptor; Ras-related C3 botulinum toxin substrate 1; sympathetic nervous system HIGH LEVELS of dietary salt intake can induce hypertension, with salt restriction being one of the most effective treatments for this condition (32,72,79). Hypertensive patients, however, exhibit a large spectrum of salt sensitivity (71), with the mechanisms determining salt sensitivity as yet incompletely understood.Several factors influence salt sensitivity, including the activities of the sympathetic nervous system (SNS), the reninangiotensin system (RAS), aldosterone, and insulin. In the Guytonian model, dysfunctional excretion of renal Na ϩ plays a major role in Na ϩ retention and salt-sensitive hypertension (42). Several genes have been found to cause rare Mendelian forms of human hypertension (134), with these findings providing insights into the basic mechanisms of human hypertension and highlighting the key role of altered Na ϩ handling by the kidneys as a final common pathway in the pathogenesis of hypertension. In...