Myocardial Glucose Transport System Related Proteins: the Effects of Aging and Exercise in Old Mice
Year: 1997
Type: dissertation
Abstract: This thesis comprises two related studies:"The effects of age on myocardial glucose transport system related proteins of the mouse."This study examined the effects of aging on the myocardial protein content of Glut 4, Glut 1, insulin receptor, IGF-1 receptor, and PI3 kinase of the C57B1/6 Ipouse.Insulin and IGF-1 receptor autophosphorylation activity was also assessed.Glut 4 content was increased'fourfold between 22.5 and 29 mo. of age, as compared to 5 mo.animals.Glut 1 content was increased by 40% at 17 mo., returning to 5 o.levels at 29 mo.Insulin and IGF-1 receptor content decreased early g, etween 5 and 17 mo.by 20 to 35%, and remained constant until 29 mo.and 25 mo.respectively.Between 25 and 29 , mo., IGF-I protein levels deqreased to 24% of 5 mo.control.Receptor , -autophosphorylation was increased at basal and maximally stimulating (10-6 M) concentrations of insulin or IGF-1 by two to fourfold.PI3 kinase content decreased 30% by 12 mo.and remained constant thereafter.We conclude that the components of the myocardial glucose transport system studied here are upregulated with advancing age in accordance to the increased importance of cardiac glucose metabolism with aging."The effects of exercise on glucose transport system related proteins of the aged mouse myocardium."The effects of 9 months of chronic voluntary exercise, 2.5 hours of forced acute exercise, and a combination of both treatments, on content of myocardial glucose transport system related proteins were assessed in 24 month old C57B1/6 mice.Specifically, ventricular content of Glut 4 and Glut 1 transporters, insulin and IGF-1 recepiors, and PI3 f kinase was quantified by immunoblot.Chronic exercise was ineffective at altering the contents of any proteins, but potentiated the effects of acute exercise.Acute exercise irt combination with chronic exercise caused increases of 114'X~in Glut 1 content and 33% in PI3 kinase~content, expressed per mg wet tissue.Acute exercise alone or in combination with chronic exercise , + .decreased insulin receptor content by 34% and 44% respectively.We conclude C that the aged mouse myocardial glucose transport system retains the capacity to respond to exercise.
Author: Corine Martineau
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2100154584