The effects of postural changes on ADH release and the renal handling of sodium and water in patients with idiopathic edema.

Abstract

In order to investigate the role of ADH and the renal handling of sodium and water in patients with idiopathic edema, 21 patients were subjected to acute oral water load tests. Although a normal water diuresis was observed in all patients in supine posture, it was markedly impaired in upright posture with significant decreases in sodium, free water, and osmolar clearances. In particular, two patients exihibited the continuous production of concentrated urine after the water load in upright posture. The fractional reabsorption of sodium at the proximal tubules was significantly increased in upright posture, while the glomerular filtration rate did not change significantly. The constricting of both legs with elastic bandages tended to improve the water diuresis in upright posture, suggesting that the pooling of blood into the lower legs might be contributing to the formation of idiopathic edema. The patients showed normal osmoregulation of ADH release in supine, but not in upright posture: the suppression of ADH release in upright posture was only transient or incomplete despite a sufficient fall in plasma osmolality following the water load. Thus, both an increase in renal sodium reabsorption and the insufficient suppression of ADH release in upright posture might contribute to the retention of body fluid in patients with idiopathic edema.

Impairment of antidiuretic hormone and atrial natriuretic peptide regulation in the obese woman with a swelling syndrome and an increase in capillary permeability to albumin

“…21,22 In our patients the percentage of water load eliminated in the urine in the four hours following the load was lower than in normal women investigated similarly by Antidiuretic hormone and natriuretic peptide in obese women P Valensi et al other authors (mean value about 110%). 8,9 The free water clearance was lower in the upright than in the recumbent position only in the obese patients. This suggests that the water load-induced inhibition of ADH secretion was lower in the upright position, and that this disorder is more marked in the obese patients with a swelling syndrome.…”

“…The lower diuresis after water load in the upright position is one of the characteristics of idiopathic oedema. 8,9 Various hormonal disorders may play a pathophysiological role. An increase in aldosterone secretion was found several years ago.…”

“…Thus both an increase in renal sodium reabsorption and the insuf®-cient suppression of ADH release in the upright posture might contribute to the retention of bodȳ uid. 9 Obesity is associated with expanded circulatory volume and an increased extracellular to intracellular uid ratio, 10 and an enhanced body sodium content has been reported in obese subjects. 11 Alterations in the renin-angiotensin system and in sympathetic activity have also been involved in the development of hypertension in obesity.…”

A Case of Secondary Aldosteronism Similar to Bartter's Syndrome with No Abnormality in Renal Chloride Reabsorption.

“…To examine renal electrolyte metabolism in the renal distal tubules, water loading test was performed by the previously reported method (Ota et al 1984) in the patient and a healthy volunteer. Twenty ml per kg (body weight) of water was orally administered.…”

Cyclical Edema in a Patient with Hypothalamic Disorders and Chronic Glomerulonephritis: Arginine Vasopressin-Dependent Atrial Natriuretic Hormone Release.

“…Edema may be aggravated in the legs and feet after prolonged orthostasis and be accompanied by diurnal weight gain in excess of 1.4kg [1]. Its pathogenesis is unknown, but it has been argued that a fall in plasma volume due to increased vascular permeability, microangiopathy or impaired protein synthesis activates the reninangiotensin-aldosterone (RAA) system and the release of arginine vasopressin (AVP), thereby resulting in the retention of salt and water [2][3][4][5]. On the other hand, cyclical edema has been reported to be concerned with abnormalities in the release of gonadal, hypophysioadrenocortical and thyroid hormones [6][7][8][9][10] creased in inverse proportion to the increase in the dose of diuretics, but cyclical edema and changes in body weight continued during the observation.…”