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Published on: August 14, 2013
Elevated NEFA levels impair glucose effectiveness by increasing net hepatic glycogenolysis
S Kehlenbrink1, S Koppaka, M Martin
1Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
Diabetologia
|August 1, 2012
Summary
Acute hyperglycemia normally suppresses glucose production in non-diabetics. In type 2 diabetes, elevated non-esterified fatty acids (NEFA) impair this glucose effectiveness, leading to higher blood sugar.
Area of Science:
- * Endocrinology
- * Metabolism
- * Physiology
Background:
- * Acute hyperglycemia effectively suppresses endogenous glucose production (EGP) in healthy individuals, primarily via glycogenolysis inhibition.
- * Impaired glucose effectiveness is a hallmark of type 2 diabetes, contributing to fasting hyperglycemia.
- * Elevated non-esterified fatty acids (NEFA) are implicated in impaired glucose effectiveness, but the precise mechanisms remain unclear.
Purpose of the Study:
- * To investigate how elevated NEFA levels affect the capacity of hyperglycemia to regulate EGP pathways.
- * To elucidate the role of NEFA in modulating hepatic glucose metabolism during hyperglycemia.
Main Methods:
- * Utilized 4-hour pancreatic clamp studies in seven non-diabetic participants.
- * Quantified glucose fluxes using D-[6,6-(2)H(2)]glucose tracer.
- * Measured hepatic glycogen concentrations via (13)C magnetic resonance spectroscopy under euglycemic, hyperglycemic, and hyperglycemic with elevated NEFA (HY-NEFA) conditions.
Main Results:
- * Hyperglycemia suppressed EGP, but this effect was abolished in the HY-NEFA condition.
- * Hepatic glycogen concentration decreased significantly in HY-NEFA compared to hyperglycemic conditions.
- * Hyperglycemia decreased gluconeogenesis, whereas HY-NEFA increased it.
Conclusions:
- * Elevated NEFA levels significantly impair the ability of hyperglycemia to inhibit net glycogenolysis.
- * This blunting of glucose effectiveness by NEFA may contribute to the pathophysiology of type 2 diabetes.
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