Related Experiment Videos
Aging and ATPase activities in rat jejunum.
M Tosco1, M N Orsenigo, S Zoppi
1Dipartimento di Fisiologia e Biochimica Generali, Universita' di Milano, Italy.
Mechanisms of Ageing and Development
|December 1, 1990
Summary
Aging reduces the activity of sodium-potassium ATPase (Na,K-ATPase) and ouabain-insensitive sodium ATPase in rat intestinal cells. Enzyme kinetics remain unchanged, indicating a quantitative decline with age.
Area of Science:
- Biochemistry
- Cell Biology
- Physiology
Background:
- The basolateral membrane of intestinal and renal cells exhibits ouabain-insensitive Na-ATPase activity alongside the well-known (Na,K)-ATPase.
- Understanding age-related changes in these membrane transport proteins is crucial for cellular function.
Purpose of the Study:
- To investigate the impact of aging on Na-ATPase and (Na,K)-ATPase activities in the basolateral membrane of rat jejunal enterocytes.
- To analyze the kinetic properties of these ATPases in relation to age.
Main Methods:
- Isolation of basolateral membranes from rat jejunal enterocytes across different age groups (very young, young, adult, old) using Percoll-gradient centrifugation.
- Quantification of total protein content, dry weight, and ATPase activities (Na-ATPase and (Na,K)-ATPase) in homogenates and isolated membrane fractions.
Main Results:
- Both Na-ATPase and (Na,K)-ATPase activities, along with protein content, decrease with age in the basolateral membrane fraction, relative to dry weight.
- This age-related diminution is also observable in the initial homogenate.
- Kinetic parameters (Km and Vmax) for Na-ATPase (hyperbolic curve) and (Na,K)-ATPase (sigmoidal curve) remain unaffected by aging.
Conclusions:
- Na-ATPase and (Na,K)-ATPase in the enterocyte basolateral membrane maintain their characteristic kinetic properties throughout an animal's lifespan.
- There is a significant quantitative decrease in the activity of both Na-ATPase and (Na,K)-ATPase with advancing age.