Leslie Carter

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Glycogen synthase (GS) activity is reduced in skeletal muscle of type 2 diabetes, despite normal protein expression, consistent with altered GS regulation. Glycogen synthase kinase-3 (GSK-3) is involved in regulation (phosphorylation and deactivation) of GS. To access the potential role of GSK-3 in insulin resistance and reduced GS activity in type 2(More)
Glycogen synthase kinase (GSK)-3 has been implicated in the regulation of multiple cellular physiological processes in skeletal muscle. Selective cell-permeable reversible inhibitors (INHs) of GSK-3 (CT98014 and CHIR98023 [Chiron, Emeryville, CA] and LiCl) were used to evaluate the role of GSK-3 in controlling glucose metabolism. Acute treatment (30 min) of(More)
Aims/hypothesis. To determine the independent and potentially synergistic effects of agonists for PPARγ and RXR on glucose and lipid metabolism, as well as gene expression, in human skeletal muscle cell cultures. Methods. Fully differentiated myotubes from non-diabetic subjects and subjects with Type II (non-insulin-dependent) diabetes mellitus were(More)
Insulin signaling pathways potentially involved in regulation of skeletal muscle glycogen synthase were compared in differentiated human muscle cell cultures from nondiabetic and type 2 diabetic patients. Insulin stimulation of glycogen synthase activity as well as phosphorylation of MAPK, p70 S6 kinase, and protein kinase B (Akt) were blocked by the(More)
Human erythrocytes have specific insulin receptors. A radloreceptor assay for the determination of Insulin binding to these receptors is presented. After two passages over a Boyum-type adient, erythrocytes from freshly collected heparinized blood were isolated and 3.5 X iO erythrocytes per milliliterwere incubated for 2.5 h in a modified pH 8.0(More)
Aims/hypothesis. To evaluate the tissue distribution and possible role of the peroxisome proliferator-activated receptors (PPARs) in insulin action in fat and muscle biopsy specimens from lean, obese and subjects with Type II (non-insulin-dependent) diabetes mellitus.¶Methods. We measured PPARα, PPARβ(δ) and PPARγ protein expression by western blot(More)
Chronic exposure (48 h) to glucosamine resulted in a dose-dependent reduction of basal and insulin-stimulated glucose uptake activities in human skeletal muscle cell cultures from nondiabetic and type 2 diabetic subjects. Insulin responsiveness of uptake was also reduced. There was no change in total membrane expression of either GLUT1, GLUT3, or GLUT4(More)
We examined the regulation of free fatty acid (FFA, palmitate) uptake into skeletal muscle cells of nondiabetic and type 2 diabetic subjects. Palmitate uptake included a protein-mediated component that was inhibited by phloretin. The protein-mediated component of uptake in muscle cells from type 2 diabetic subjects (78 +/- 13 nmol. mg protein-1. min-1) was(More)
The relationship between insulin action and control of the adipocyte-derived factor adiponectin was studied in age- and weight-matched obese individuals with type 2 diabetes failing sulfonylurea therapy. After initial metabolic characterization, subjects were randomized to troglitazone or metformin treatment groups; all subjects received glyburide (10 mg(More)
The aim of this study was to determine whether the long-acting insulin analog, insulin glargine, behaves like human insulin for metabolic and mitogenic responses in differentiated cultured human skeletal muscle cells from nondiabetic and diabetic subjects. Human insulin and insulin glargine were equipotent in their ability to compete for [(125)I]insulin(More)