Related Experiment Videos
Impaired urinary concentrating ability in genetically polyuric mice
Sumiko Homma1, Sigeyuki Takeda, Eiji Kusano
1Department of Nephrology, Jichi Medical School, Minamikawachi, Tochigi, Japan. sumiho@jichi.ac.jp
Nephron
|October 26, 2002
Summary
A new strain of polyuric (PUS) mice exhibits hereditary kidney dysfunction. These mice show impaired renal response to vasopressin (AVP), leading to reduced urine concentration ability.
Area of Science:
- Nephrology
- Molecular Endocrinology
- Genetics
Background:
- Hereditary polyuria is a condition characterized by excessive urination.
- Understanding the genetic and molecular basis of polyuria is crucial for diagnosing and treating kidney disorders.
Purpose of the Study:
- To characterize a newly identified strain of mice with hereditary polyuria (PUS mice).
- To investigate the underlying mechanisms of renal dysfunction and impaired urine concentrating ability in PUS mice.
Main Methods:
- Characterization of PUS mice for polyuria and urine concentrating ability.
- In vivo studies assessing response to water deprivation and dDAVP infusion.
- In vitro microanalysis of isolated tubular segments to measure cyclic AMP (cAMP) accumulation and adenylate cyclase (AdC) activity.
Main Results:
- PUS mice exhibited significant polyuria and hypotonic urine compared to controls.
- Renal resistance to arginine vasopressin (AVP) was indicated by blunted responses in vivo.
- Impaired AVP-induced cAMP accumulation in cortical collecting ducts (CCDs) of PUS mice was linked to reduced basal and stimulated AdC activity.
Conclusions:
- Hereditary polyuria in PUS mice is an autosomal-recessive trait.
- The primary defect appears to be impaired cAMP signaling in the CCDs, likely due to reduced adenylate cyclase activity.
- This molecular defect contributes to the observed renal resistance to AVP and impaired urine concentrating ability.