endothelin-1 and Water-Electrolyte-Imbalance

1. Endothelin (ET)-1, which was originally found to be secreted by the vascular endothelium, is highly expressed in the kidney, particularly in the renal medulla. 2. Recent studies using genetic models have provided significant breakthroughs in the role of ET-1 in the kidney. For example, ET-1 in the medullary collecting duct physiologically regulates water and salt reabsorption, thereby controlling blood pressure. Surprisingly, to explain the blood pressure regulation both ET(A) and ET(B) receptors are necessary in collecting duct. In fact, we recently revealed that ET(A) receptor stimulation in the renal medulla was natriuretic and diuretic. 3. The expression and secretion of ET-1 in the renal medulla are regulated by multiple mechanisms, such as changes in osmolality, exaggerated renin-angiotensin system activity and hypoxia. The changes in the renal medullary ET system are likely to work as compensatory 'protective' natriuretic factors in response to high sodium exposure in the kidney. 4. In the present review, we focus on recent publications that describe our current knowledge of the functional role of renal medullary ET-1, including the recently characterized actions of ET(A) receptors, the second messenger systems, mechanisms of stimulating ET-1 production and how the ET system is involved in the development of hypertension.

Topics: Animals; Endothelin-1; Humans; Hypertension; Kidney Medulla; Natriuresis; Receptor, Endothelin A; Receptor, Endothelin B; Renin-Angiotensin System; Second Messenger Systems; Sodium Chloride, Dietary; Water-Electrolyte Balance; Water-Electrolyte Imbalance

The aim was to evaluate the factors determining preoperative renal dysfunction in patients with obstructive jaundice.. In a prospective cross-sectional observational study, 63 patients, 27 with benign and 36 with malignant obstructive jaundice, were investigated at admission and compared with 25 healthy control subjects. Variables analysed included extracellular body water (ECW) compartment, plasma levels of aldosterone, renin, atrial natriuretic peptide, vasopressin, nitric oxide, endothelin (ET) 1 and prostaglandin E2 (PGE2), urinary nitric oxide and PGE2, serum albumin and renal function.. The metabolic profile of obstructive jaundice was characterized by a depletion of the ECW (P = 0.004), and increased plasma levels of atrial natriuretic peptide (P < 0.001), ET-1 (P = 0.044), vasopressin (P = 0.017), aldosterone (P = 0.005) and renin (P = 0.001). Increased plasma (P < 0.001) and urinary (P = 0.001) PGE2 levels were also found. Fifty-four per cent of patients had a creatinine clearance of less than 70 ml/min. In multivariate analysis, serum bilirubin, renin, ET-1, PGE2, decreased urinary sodium excretion and age were identified as predictors of renal dysfunction.. Renal dysfunction in patients with obstructive jaundice was associated with the degree of biliary obstruction, age of the patient and reduced urinary sodium excretion. These alterations were closely related to derangements in sodium- and water-regulating hormones.

Topics: Atrial Natriuretic Factor; Dinoprostone; Endothelin-1; Female; Humans; Jaundice, Obstructive; Kidney Diseases; Male; Middle Aged; Multivariate Analysis; Prospective Studies; Regression Analysis; Risk Factors; Water-Electrolyte Imbalance