Abstract
Vasopressin was administered daily with a forced water load to six trained dogs. Antidiuresis and natriuresis were observed in the dogs. After the initial few days of antidiuresis, vasopressin escape developed. The antidiuretic response to vasopressin became greatly reduced despite the continued administration of the hormone; natriuresis, however, remained. Vasopressin escape was found to develop only in the presence of chronic overhydration. In the absence of overhydration, daily administration of vasopressin for a much longer duration did not result in a loss of antidiuretic response to vasopressin. It was also found that vasopressin escape occurred independently of renal hemodynamic changes. Analyses of renal tissue osmolality and electrolytes revealed that kidneys from dogs with vasopressin escape had a marked loss of corticomedullary osmatic gradient. It is concluded that vasopressin escape results not from a prolonged exposure of the kidney tissue to the hormone but is related to a dissipation of corticomedullary osmotic gradient consequent to overhydration.
Footnotes
- Received April 24, 1972.
- Accepted September 27, 1972.
- © 1973 by The Williams & Wilkins Company
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|