OBJECTIVE To determine the mechanism by which the bile acid sequestrant colesevelam improves glycemic control. RESEARCH DESIGN AND METHODS We performed a frequently sampled intravenous glucose tolerance test (FSIGT) with minimal model analysis and a meal tolerance test (MTT) in 20 subjects with impaired fasting glucose (11 men, 9 women; mean age 60.7 ± 1.9 years, BMI 29.4 ± 0.9 kg/m(2)) in a ...

Male domestic cats that are neutered and overweight are at an increased risk for developing a type-2-like diabetes mellitus. Beneficial effects of 17β-estradiol (E2) on glucose homeostasis may be lost with neutering and thereby account for increased diabetes risk. To evaluate this, adult male neutered overweight cats (n=6) were given daily E2 (1.0 μg/kg) or vehicle (Vh; ethanol, 1.0 μL/kg) in a...

The quantity of deuterated glucose customarily given in labelled IVGTTs (intravenous glucose tolerance tests) changes the isotopic composition of the subject's body water enough to be detected by mass spectrometric techniques. Glucose undergoing direct glycogenesis does not contribute label to the body water pool, and isotope incorporated into it must have come from glucose that has either been...

The Intra Venous Glucose Tolerance Test (IVGTT) is an experimental procedure in which a challenge bolus of glucose is administered intra-venously and plasma glucose and insulin concentrations are then frequently sampled. An open problem is to construct a model representing simultaneously the entire control system. In the last three decades, several models appeared in the literature. One of the ...

OBJECTIVE To investigate the relationship of the K121Q polymorphism of the plasma cell glycoprotein 1 (PC-1) gene with insulin resistance, insulin secretion, and lipids and lipoproteins. RESEARCH DESIGN AND METHODS Altogether, 110 normoglycemic subjects (group I) underwent a hyperinsulinemic-euglycemic clamp for evaluation of insulin sensitivity. The first-phase insulin secretion was determin...

Glucose tolerance decreases with age. For determining the cause of this decrease, 67 elderly and 21 young (70.1 +/- 0.7 vs. 23.7 +/- 0.8 years) participants ingested a mixed meal and received an intravenous injection of glucose. Fasting glucose and the glycemic response above basal were higher in the elderly than in the young participants after either meal ingestion (P < 0.001) or glucose injec...

The hyperglycemic effects of epinephrine (Epi) are established; however, the modulation of Epi-stimulated endogenous glucose production (EGP) by glucose and insulin in vivo in humans is less clear. Our aim was to determine the effect of exogenously increased plasma Epi concentrations on insulin and glucose dynamics. In six normal control subjects, we used the labeled intravenous glucose toleran...

Recently, several in vitro studies have shown that GPR40 receptor activation by free fatty acids (FFAs) results in glucose-dependent insulin secretion. However, whether GPR40 receptor activation results in glucose-dependent insulin secretion in vivo in rats is not known. Therefore, we evaluated the effect of synthetic GPR40 receptor agonist (compound 1) on glucose tolerance test (GTT) in fed, f...

BACKGROUND During the prediabetic development, the changes in β-cell function and tissue-specific insulin resistance have been described. However, there are conflicting views in insulin secretory capacity between early clinical observation and recent proposed mathematical model. On the basis of digestive and metabolic similarities with humans, swine have great potential as an animal model to in...