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United States Department of Agriculture

Agricultural Research Service

Title: Regulation of Ptp-1 and Insulin Receptor Kinase by Fractions from Cinnamon:implications for Cinnamon Regulation of Insulin Signalling

Authors
item Radosevich, Jennifer - IOWA STATE UNIV
item Deas, Shenequa - IOWA STATE UNIV
item Polansky, Marilyn
item Baedke, Deborah - IOWA STATE UNIV
item Ingebritsen, Thomas - IOWA STATE UNIV
item Anderson, Richard
item Graves, Donald - IOWA STATE UNIV

Submitted to: Hormone Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 15, 1998
Publication Date: N/A

Interpretive Summary: There are approximately 15 million people in the United States with type II diabetes and over half of these people are unaware they have the disease. Even larger numbers of people have elevated levels of blood sugar that may lead to diabetes. Diet is known to help control impaired glucose metabolism and type II diabetes but the exact components of the diet involved are unclear. We have shown that the common spice, cinnamon, may be a critical dietary component in the control of blood sugar. We have also demonstrated a mechanism or pathway where components of cinnamon act in the regulation of blood sugar. This work has the potential to be of benefit to the millions of people with elevated levels of blood sugar and diabetes throughout the world. This work is also of benefit to scientists and medical personnel interested in the mechanisms of control of sugar utilization.

Technical Abstract: Bio-active compound(s) extracted from cinnamon potentiate insulin activity, as measured by glucose oxidation in the rat epididymal fat cell assay. Wortmannin, a potent PI 3'-kinase inhibitor, decreases the biological response to insulin and bio-active compound(s) from cinnamon similarly, indicating that cinnamon is affecting an element(s) upstream of PI 3'-kinase. Enzyme studies done in vitro show that the bio-active compound(s) can stimulate autophosphorylation of a truncated form of the insulin receptor and can inhibit PTP-1, a rat homolog of a tyrosine phosphatase (PTP-1B) that inactivates the insulin receptor. No inhibition was found with alkaline phosphatase or calcineurin suggesting that the active material is not a general phosphatase inhibitor. It is suggested, then, that a cinnamon compound(s), like insulin, affects protein phosphorylation-dephosphorylation reactions in the intact adipocyte. Bio-active cinnamon compounds may find further use in studies of insulin resistance in adult onset diabetes.

Last Modified: 4/19/2014
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