Oral chromium picolinate improves carbohydrate and lipid metabolism and enhances skeletal muscle Glut-4 translocation in obese, hyperinsulinemic (JCR-LA corpulent) rats.
Human studies suggest that chromium picolinate (CrPic) decreases insulin levels and improves glucose disposal in obese and type 2 diabetic populations. To evaluate whether CrPic may aid in treatment of the insulin resistance syndrome, we assessed its effects in JCR:LA-corpulent rats, a model of this syndrome. Male lean and obese hyperinsulinemic rats were randomly assigned to receive oral CrPic [80 microg/(kg. d); n = 5 or 6, respectively) in water or to control conditions (water, n = 5). After 3 mo, a 120-min intraperitoneal glucose tolerance test (IPGTT) and a 30-min insulin tolerance test were performed. Obese rats administered CrPic had significantly lower fasting insulin levels (1848 +/- 102 vs. 2688 +/- 234 pmol/L; P < 0.001; mean +/- SEM) and significantly improved glucose disappearance (P < 0.001) compared with obese controls. Glucose and insulin areas under the curve for IPGTT were significantly less for obese CrPic-treated rats than in obese controls (P < 0.001). Obese CrPic-treated rats had lower plasma total cholesterol (3.57 +/- 0.28 vs. 4.11 +/- 0.47 mmol/L, P < 0.05) and higher HDL cholesterol levels (1.92 +/- 0.09 vs. 1.37 +/- 0.36 mmol/L, P < 0.01) than obese controls. CrPic did not alter plasma glucose or cholesterol levels in lean rats. Total skeletal muscle glucose transporter (Glut)-4 did not differ among groups; however, CrPic significantly enhanced membrane-associated Glut-4 in obese rats after insulin stimulation. Thus, CrPic supplementation enhances insulin sensitivity and glucose disappearance, and improves lipids in male obese hyperinsulinemic JCR:LA-corpulent rats.
Cefalu
William T
WT
Department of Medicine, University of Vermont College of Medicine, Burlington, VT, USA. William.Cefalu@uvm.edu
Wang
Zhong Q
ZQ
Zhang
Xian H
XH
Baldor
Linda C
LC
Russell
James C
JC
D000284:Administration, Oral; D000818:Animals; D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism; D050260:Carbohydrate Metabolism; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000378:metabolism; D004195:Disease Models, Animal; D005951:Glucose Tolerance Test; D051275:Glucose Transporter Type 4; D006946:Hyperinsulinism / Q000188:drug therapy / Q000378:metabolism; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D007502:Iron Chelating Agents / Q000008:administration & dosage* / Q000494:pharmacology; D050356:Lipid Metabolism; D008297:Male; D024821:Metabolic Syndrome / Q000502:physiology; D009004:Monosaccharide Transport Proteins / Q000187:drug effects / Q000378:metabolism*; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D009765:Obesity / Q000188:drug therapy / Q000378:metabolism*; D010848:Picolinic Acids / Q000008:administration & dosage* / Q000494:pharmacology; D011897:Random Allocation; D051381:Rats
D001786:Blood Glucose; D051275:Glucose Transporter Type 4; D007328:Insulin; D007502:Iron Chelating Agents; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D010848:Picolinic Acids; C495694:Slc2a4 protein, rat; C030614:picolinic acid