Effects of pyruvate on the metabolism and insulin resistance of obese Zucker rats.
Female obese Zucker rats aged 5 wk were randomly assigned to a control diet or one of two experimental diets. Experimental diets contained 6% of energy as pyruvate in the form of calcium-pyruvate (Ca-pyr) or 6% pyruvylglycine (pyr-gly). Diets were pair-fed according to the experimental group with the lowest food consumption. During the 3 wk of dietary treatment, Ca-pyr- and pyr-gly-fed rats gained significantly less weight, had a lower food-conversion efficiency, and maintained a higher resting oxygen consumption (mL.min-1 x kg-0.67) than control rats. Ca-pyr and pyr-gly also lowered the respiratory exchange ratio of the rats resulting in a 90% increase in their lipid oxidation and a 50% decrease in their carbohydrate oxidation. Glucose tolerance, assessed by an oral glucose load, was not different among treatments, but the insulin response of the pyr-gly-fed rats was significantly less than that of the control rats despite elevated plasma triglyceride concentrations in the pyr-gly-fed rats (control, 1.43 +/- 0.16 vs pyr-gly, 3.76 +/- 0.87 mmol/L). These results suggest that pyr-gly, like Ca-pyr, favorably alters the metabolism of obese Zucker rats. In addition, pyr-gly appeared to reduce the insulin resistance that develops spontaneously in obese rats.
Ivy
J L
JL
Department of Kinesiology, University of Texas at Austin 78712.
Cortez
M Y
MY
Chandler
R M
RM
Byrne
H K
HK
Miller
R H
RH
D000704:Analysis of Variance; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight / Q000187:drug effects; D002784:Cholesterol / Q000097:blood; D004734:Energy Metabolism / Q000187:drug effects; D005260:Female; D005951:Glucose Tolerance Test; D005998:Glycine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D006003:Glycogen / Q000032:analysis; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D007333:Insulin Resistance; D008055:Lipids / Q000097:blood; D009765:Obesity / Q000188:drug therapy* / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D011773:Pyruvates / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D019289:Pyruvic Acid; D011897:Random Allocation; D051381:Rats; D011924:Rats, Zucker; D013997:Time Factors; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D007328:Insulin; D008055:Lipids; D011773:Pyruvates; D014280:Triglycerides; C085808:pyruvylglycine; D019289:Pyruvic Acid; D006003:Glycogen; D002784:Cholesterol; D005998:Glycine