Insulin action on glucose and protein metabolism during L-carnitine supplementation in maintenance haemodialysis patients.
BACKGROUND
Impaired protein anabolism and insulin resistance are characteristic features of maintenance haemodialysis patients. We have used a randomised, matched-paired, double-blind, placebo-controlled experimental design to determine the capability of intravenous L-carnitine supplementation to modify insulin resistance and protein catabolism in non-diabetic patients with end-stage renal disease (ESRD) undergoing chronic haemodialysis treatment.


METHODS
L-carnitine (20 mg x kg(-1)) (n = 9) or placebo (n = 10) were given intravenously at the end of seven consecutive dialysis sessions. Whole-body protein and glucose metabolism were assessed on interdialytic days by the L[1-(13)C]leucine and the [2,2-(2)H(2)]glucose kinetic models in the postabsorptive state and during euglicemic hyperinsulinemic clamp studies at baseline and at the end of the treatment period.


RESULTS
L-carnitine supplementation was associated with lower (P < 0.05) rates of leucine oxidation (-11 +/- 12%) and appearance from proteolysis (-6 +/- 2%) during the clamp studies than after placebo supplementation. The rates of glucose appearance in the postabsorptive state did not change significantly in the patients receiving L-carnitine treatment. Insulin-mediated glucose disappearance was improved by L-carnitine only in those patients (n = 5) (+18 +/- 3%, P < 0.05 vs placebo group, n = 5) with greater baseline insulin resistance, selected according to the median value of insulin sensitivity before treatment.


CONCLUSIONS
L-carnitine supplementation was associated with protein-sparing effects in maintenance haemodialysis patients during hyperinsulinemia.
Biolo
Gianni
G
Department of Clinical Morphological Technological Sciences, Division of Internal Medicine, University of Trieste, Trieste, Italy. biolo@units.it
Stulle
Manuela
M
Bianco
Francesco
F
Mengozzi
Giuseppe
G
Barazzoni
Rocco
R
Vasile
Alfonso
A
Panzetta
Giovanni
G
Guarnieri
Gianfranco
G
D000368:Aged; D002331:Carnitine / Q000008:administration & dosage / Q000494:pharmacology*; D004311:Double-Blind Method; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007275:Injections, Intravenous; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology; D007676:Kidney Failure, Chronic / Q000378:metabolism* / Q000628:therapy*; D007930:Leucine / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011506:Proteins / Q000378:metabolism*; D006435:Renal Dialysis
D007328:Insulin; D011506:Proteins; D007930:Leucine; D005947:Glucose; D002331:Carnitine