The rate of ATP export in the extramitochondrial phase via the adenine nucleotide translocator changes in aging in mitochondria isolated from heart left ventricle of either normotensive or spontaneously hypertensive rats.

Abstract

To find out whether and how deficit of cellular energy supply from mitochondria to cytosol occurs in aging and hypertension, we used mitochondria isolated from 5 to 72 week-old heart left ventricle of either normotensive (WKY) or spontaneous hypertensive (SH) rats as a model system. Measurements were made of the rate of ATP appearance outside mitochondria, due to externally added ADP, as an increase of NADPH absorbance which occurs when ATP is produced in the presence of glucose, hexokinase and glucose-6-phosphate dehydrogenase. Such a rate proved to mirror the function of the adenine nucleotide translocator (ANT) rather than other processes linked to the both oxidative and substrate level phosphorylation. The changes in both Ki for atractyloside and Km for ADP suggest the occurrence of modification of the ANT conformation during aging in which the ANT Vmax was found to decrease in normotensive but to increase under spontaneously hypertension in 24 week-old rats with a subsequent decrease in both cases. ANT function, as investigated in the ADP physiological range (20-60μM), is expected to decrease in normotensive, but to increase in hypertensive rats up to 48 weeks. Later a decrease in the ATP rate of export outside mitochondria should occur in both cases.

• Authors: Anna Atlante, Teresa Maria Seccia, Ersilia Marra, Salvatore Passarella
• Journal: Mechanisms of ageing and development (Mech Ageing Dev) Vol. 132 Issue 10 Pg. 488-95 (Oct 2011) ISSN: 1872-6216 [Electronic] Ireland
• PMID: 21855562 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Chemical References

• Atractyloside
• NADP
• Adenosine Diphosphate
• Adenosine Triphosphate
• Mitochondrial ADP, ATP Translocases

Topics

• Adenosine Diphosphate (metabolism)
• Adenosine Triphosphate (metabolism)
• Aging (metabolism)
• Animals
• Atractyloside (pharmacology)
• Biological Transport, Active
• Energy Metabolism
• Heart Ventricles (metabolism)
• Hypertension (metabolism)
• In Vitro Techniques
• Kinetics
• Male
• Mitochondria, Heart (drug effects, metabolism)
• Mitochondrial ADP, ATP Translocases (antagonists & inhibitors, metabolism)
• Models, Cardiovascular
• NADP (biosynthesis)
• Oxygen Consumption
• Rats
• Rats, Inbred SHR
• Rats, Inbred WKY