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Plasma vasopressin and cortical nephron function in aging rats
1Département de Biologie Cellulaire et Moléculaire, CEN Saclay, Gifsur Yvette, France.
Mechanisms of Ageing and Development
|March 1, 1992
Summary
Aging kidneys show reduced urine concentration and increased volume due to impaired vasopressin response, not Henle's loop transport issues. This age-related polyuria suggests other nephron segments are affected.
Area of Science:
- Nephrology
- Gerontology
- Physiology
Background:
- Age-related polyuria and decreased urine osmolality are common in older mammals.
- The roles of vasopressin and Henle's loop transport in these age-related changes are not fully understood.
Purpose of the Study:
- To investigate the contribution of vasopressin and Henle's loop transport to age-related polyuria and reduced urine osmolality in female WAG/Rij rats.
Main Methods:
- Micropuncture studies were performed on cortical nephrons of rats aged 10, 20, and 30 months.
- Plasma vasopressin concentrations were measured.
- Tubular fluid osmolality and single nephron filtration rates were analyzed.
Main Results:
- Urine osmolality decreased and urinary volume increased with age.
- Plasma vasopressin levels remained unchanged across age groups.
- Henle's loop transport, diluting capacity, and filtration rates were similar in young and old rats.
Conclusions:
- Age-related polyuria is not caused by reduced vasopressin or impaired Henle's loop transport.
- The findings suggest an impaired kidney response to vasopressin in other nephron segments, likely the medullary thick ascending limb or collecting duct.