IMPAIRMENT OF ANTIDIURETIC-HORMONE AND ATRIAL-NATRIURETIC-PEPTIDE REGULATION IN THE OBESE WOMAN WITH A SWELLING SYNDROME AND AN INCREASE INCAPILLARY-PERMEABILITY TO ALBUMIN

OBJECTIVE: To study the regulation of antidiuretic hormone (ADH) and a trial natriuretic peptide (ANP) in obese and lean women with a swellin g syndrome. PATIENTS: Thirty-four obese women and 12 lean women with a swelling syndrome and an abnormal isotopic test of capillary permeabi lity to albumin were investigated MEASUREMENTS: After 10 nocturnal hou rs of fluid restriction, subjects were asked at 8 am to ingest a tap w ater load of 20 ml/kg within 10 min and to remain strictly recumbent u ntil twelve noon on the first day, and to remain standing and to walk around until twelve noon on the second day. Free water clearance and t he cGMP/creatinine and albumin/creatinine ratios were determined hourl y in the morning. RESULTS: The total 4 h-urinary volume/ingested water volume ratio was significantly lower on the second day both in the le an and the obese patients, the differences being slightly larger in th e obese patients. The increase in free water clearance was significant ly less on the second day in the obese patients. The increase in cGMP/ creatinine ratio was also significantly lower on the second day in the obese patients. The maximum level of the urinary albumin/creatinine r atio was significantly higher on the second day in the obese patients. CONCLUSION: In obese women with a swelling syndrome: (1) The higher i ncrease in the urinary albumin excretion rate after water loading foll owed by a sustained upright position suggests a widespread alteration in capillary function, which is also indicated by the isotopic test of capillary permeability to albumin. (2) The water load-induced inhibit ion of ADH secretion and stimulation of ANP secretion or ANP activity, more defective in the upright position than in the recumbent one, is probably another major contributing factor to orthostatic oedema.