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Published on: July 3, 2013
The starved kidney: a defect in renal concentrating ability
Metabolism: Clinical and Experimental
|April 1, 1975
Summary
Obese patients undergoing starvation show reduced kidney response to antidiuretic hormone. This suggests partial insensitivity of renal tubules to antidiuretic hormone and mineralocorticoids during fasting.
Area of Science:
- Nephrology
- Endocrinology
- Metabolic Disorders
Background:
- Obesity is associated with various metabolic and endocrine dysfunctions.
- Fasting can significantly alter physiological responses, including renal function.
- The role of antidiuretic hormone (ADH) in regulating water balance is crucial, especially during altered metabolic states.
Purpose of the Study:
- To investigate the renal tubular responsiveness to antidiuretic hormone in obese individuals during starvation.
- To assess the impact of fasting on the kidney's ability to concentrate urine in response to ADH.
- To explore the relationship between ADH insensitivity and mineralocorticoid insensitivity during starvation in obese subjects.
Main Methods:
- Seven obese patients were studied.
- An overnight dehydration test was employed to assess baseline renal concentrating ability.
- Exogenous vasopressin (synthetic ADH) was administered to evaluate maximal renal response.
- Urinary osmolality was measured before and after vasopressin administration during both feeding and starvation phases.
Main Results:
- A mean reduction of one-third in maximum urinary osmolality was observed on day 4 of starvation.
- All seven subjects exhibited diminished renal response to exogenous vasopressin.
- The findings indicate partial insensitivity of the renal tubule to antidiuretic hormone during starvation.
Conclusions:
- Renal tubules in obese patients become partially insensitive to antidiuretic hormone during starvation.
- This insensitivity occurs concurrently with a diminished response to mineralocorticoids.
- Fasting-induced metabolic changes may impair the kidney's water-conserving mechanisms.
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