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Age-related changes in pancreatic islet cell gene expression
S J Giddings1, L R Carnaghi, A D Mooradian
1St. Louis Department of Veterans' Affairs Medical Center, MO.
Metabolism: Clinical and Experimental
|March 1, 1995
Summary
Aging alters pancreatic islet gene expression, affecting insulin secretion. Key genes like amylin, glucose transporter 2 (GluT2), and glucagon mRNA levels doubled, while insulin mRNA showed modest increases, impacting glucose metabolism.
Area of Science:
- Endocrinology
- Molecular Biology
- Aging Research
Background:
- Insulin secretion declines with age, but synthesis and transcription remain stable.
- Age-related changes in other pancreatic islet genes may impact function.
Purpose of the Study:
- To investigate age-related alterations in pancreatic islet gene expression.
- To quantify mRNAs for insulin I, insulin II, amylin, glucose transporter 2 (GluT2), glucagon, and glucokinase in aging rats.
Main Methods:
- Quantification of specific mRNAs using species-specific ribonuclease (RNase) protection assays.
- Analysis of gene expression in Fischer 344 rats at 2, 6, 12, and 24 months of age.
Main Results:
- Amylin, GluT2, and glucagon mRNA abundances doubled between 2 and 12 months.
- Insulin I and II mRNA levels showed a modest increase (1.2- to 1.3-fold).
- The ratio of insulin II to insulin I mRNA increased with age, independent of islet mass.
Conclusions:
- Aging significantly alters the relative expression of pancreatic islet genes.
- These changes affect genes involved in insulin secretion and intraislet glucose metabolism.