Renal response to blood volume expansion in Brattleboro rats after acute treatment with vasopressin

• Published in: Naunyn-Schmiedeberg's archives of pharmacology 1991-07, Vol.344 (1), p.119-125
• Main Authors: PALLUK, R, VERESS, A. T, SONNENBERG, H
• Format: Article
• Language: English
• Subjects: Animals; Arginine Vasopressin - pharmacology; Atrial Natriuretic Factor - blood; Biological and medical sciences; Blood Pressure - drug effects; Blood Pressure - physiology; Blood Volume - drug effects; Blood Volume - physiology; Glomerular Filtration Rate - drug effects; Kidney - anatomy & histology; Kidney - physiology; Medical sciences; Organ Size - drug effects; Pharmacology. Drug treatments; Rats; Rats, Brattleboro; Serum Albumin, Bovine - pharmacology; Urinary system; Urine; vasopressin
• ISSN: 0028-1298; 1432-1912
• DOI: 10.1007/BF00167391

The renal response to iso-oncotic blood volume expansion with bovine serum albumin was studied in anaesthetized homozygous Brattleboro (DI) rats after acute (1 day) pretreatment with 1 U arginine-vasopressin (AVP) compared to heterozygous controls. In AVP-treated DI (DI + AVP) rats, basal urine flow as well as urinary sodium, chloride, and potassium excretion, were not different from controls. Diuresis and kaliuresis induced by volume expansion were blunted in DI + AVP rats. However, natriuresis and chloruresis were exaggerated in DI + AVP rats. They increased faster, reached a higher maximum, but declined earlier, compared to controls. The blunted diuresis resulted in a positive volume balance by the end of the experiment in DI + AVP rats, whereas the controls showed restoration of normal balance. Significant retention of sodium and chloride was observed in controls, but not in DI + AVP rats, over the time of the experiment. DI + AVP rats lost significantly less potassium than controls during the experiment. As judged from the lithium clearance method, the exaggerated saluresis in DI + AVP rats was mainly due to a reduced proximal sodium reabsorption. Plasma immunoreactivity of atrial natriuretic peptide (ANP) rose during blood volume expansion and fell in the recovery period. It was not different between AVP-treated DI rats and controls at any time of the experiment. Inulin clearance was slightly, but not significantly, lower in DI + AVP rats and increased after blood volume expansion in DI + AVP rats only.