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A 54-year-old schizophrenic patient who presented with hyponatremia and nephrotic-range proteinuria was subsequently discovered to have a gastric adenocarcinoma. Psychogenic water drinking, sodium depletion, and cardiac, adrenal, hepatic, and thyroid disease were excluded as causes of hyponatremia. The serum creatinine concentration was normal, and, although renal biopsy showed changes consistent with immune complex glomerulopathy, proteinuria remitted without treatment. Moderately severe hyponatremia persisted, and the diagnosis of gastric adenocarcinoma was made after the onset of early satiety 1 year later. Surgical exploration at the time of partial gastric resection revealed local metastatic lymph node involvement. Following the patient's uneventful recovery from surgery, studies of osmoregulation of vasopressin release and renal water handling were performed to determine the cause of chronic hyponatremia refractory to sodium chloride administration. Oral water loading studies revealed normal urinary diluting ability and appropriate suppression of plasma vasopressin concentrations. However, hypertonic sodium chloride infusion studies revealed a highly significant correlation between plasma osmolality and plasma vasopressin concentration, and a low osmotic threshold for vasopressin release based on linear regression analysis of the plasma vasopressin response to increasing plasma osmolality. Low osmotic threshold for vasopressin release was confirmed by exponential (log linear) and parabolic methods of data analysis. The findings in these studies are consistent with the typical features of the reset osmostat variant of the syndrome of inappropriate antidiuresis. To our knowledge, this is the first report of the occurrence of this syndrome in association with gastric adenocarcinoma.

Arterial plasma levels and hepatic extraction of renin and aldosterone (ALDO) were measured in 24 patients with alcoholic liver disease and in 14 normal subjects being evaluated as prospective kidney donors. Patients with liver disease had higher plasma concentrations and lower fractional hepatic extractions of both renin and ALDO than the normal subjects. The quantity of renin extracted by the liver was highly correlated with plasma renin in both normal subjects and patients. Plasma ALDO concentration was positively correlated with plasma renin (p less than 0.001) but not with serum sodium, potassium or albumin concentration, inferior vena cava pressure, corrected hepatic venous wedge pressure, plasma volume or sulfobromophthalein storage or transport. Sixteen patients were restudied after one month. Six had received 40 mg/day of prednisolone, and the remaining 10 had received a placebo. Neither group had a change in plasma volume, corrected hepatic venous wedge pressure, plasma concentration or hepatic extraction of renin or ALDO. Serum albumin concentration increased and inferior vena cava pressure decreased with prednisolone therapy. These studies document high plasma levels and impaired hepatic extraction of renin and ALDO in patients with liver disease that are not corrected by short-term prednisolone therapy.