Carnitine increases glucose disposal in humans.
OBJECTIVE
The goal of this work is to assess the effect of L-carnitine on glucose disposal, particularly on insulin sensitivity, in healthy volunteers.


METHODS
Fourteen healthy human volunteers were subjected to the intravenous glucose tolerance test (analyzed by means of the minimal model technique), together with indirect calorimetry and measurement of serum free fatty acids, after a bolus of glucose plus carnitine (C) or a bolus of glucose plus saline (P).


RESULTS
The minimal model demonstrated a significant increase in glucose disposal from plasma with carnitine: Glucose effectiveness passed from 2.7%/min to 3.8%/min. No significant changes were observed in the Insulin Sensitivity Index or in Insulin/C-Peptide secretion. Calorimetry showed a significant increase in respiratory quotient, resulting from a significant increase in carbohydrate oxidation rate during carnitine administration by an average of 0.0176+/-0.0118 g/min (p=0.015). Energy expenditure was not modified by treatment. A smaller decrease in plasma fatty acid concentrations was noted with carnitine plus glucose than after glucose alone.


CONCLUSIONS
From these data it appears that carnitine stimulates glucose disposal and oxidation in the healthy volunteer. Therefore, carnitine might be useful as an adjunct in the therapy of diabetes mellitus.
De Gaetano
A
A
Consiglio Nazionale delle Ricerche, Centro Fisiopatologia Shock, Laboratorio di Biomatematica, Istituto di Clinica Medica, Università Cattolica del Sacro Cuore, Rome, Italy.
Mingrone
G
G
Castagneto
M
M
Calvani
M
M
D000328:Adult; D001786:Blood Glucose / Q000187:drug effects*; D002153:Calorimetry, Indirect; D002331:Carnitine / Q000008:administration & dosage*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D008297:Male; D012016:Reference Values; D013997:Time Factors
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D002331:Carnitine