Heterogeneity in limb fatty acid kinetics in type 2 diabetes.
OBJECTIVE
In order to test the hypothesis that disturbances in skeletal muscle fatty acid metabolism with type 2 diabetes are not equally present in the upper and lower limbs, we studied fatty acid kinetics simultaneously across the arm and leg of type 2 diabetic patients (n=6) and matched control subjects (n=7) for 5 h under baseline conditions and during a 4-h hyperinsulinaemic-euglycaemic clamp.


METHODS
Limb fatty acid kinetics was determined by means of continuous [U-(13)C]palmitate infusion and measurement of arteriovenous differences.


RESULTS
The systemic palmitate rate of appearance was 3.6+/-0.4 and 2.7+/-0.3 micromol.kg lean body mass(-1).min(-1) and decreased during the clamp by 26% (p=0.04) and 43% (p<0.01) in the diabetic patients and in the control subjects respectively. At baseline, palmitate uptake across the arm was similar in the two groups, whereas leg palmitate uptake was lower than in the arm in the diabetic patients. During the clamp, palmitate uptake decreased in the arm (-48%, p=0.02) and the leg (-38%, p=0.04) of the control subjects, whereas it decreased in the arm (-30%, p=0.04) but not in the leg of the diabetic patients. Similarly, during the clamp palmitate release was substantially suppressed in the arm (-47%, p<0.01) and the leg of the control subjects (-45%, p<0.01), but only in the arm of the diabetic patients (-45%, p<0.01).


CONCLUSIONS
The present data indicate that type 2 diabetes is characterised by heterogeneity in the dysregulation of skeletal muscle fatty acid metabolism, with only the leg, but not the arm, showing an impairment of fatty acid kinetics at baseline and during a hyperinsulinaemic-euglycaemic clamp causing a physiological increase in insulin concentration.
Sacchetti
M
M
Copenhagen Muscle Research Centre, Rigshospitalet section 7652, 9 Blegdamsvej, 2100 Copenhagen, Denmark. msacchetti@cmrc.dk
Olsen
D B
DB
Saltin
B
B
van Hall
G
G
D001132:Arm / Q000098:blood supply; D001692:Biological Transport; D001783:Blood Flow Velocity; D001823:Body Composition; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood / Q000378:metabolism*; D005263:Femoral Artery; D005268:Femoral Vein; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D019308:Palmitic Acid / Q000097:blood / Q000378:metabolism; D012016:Reference Values
D005230:Fatty Acids, Nonesterified; D019308:Palmitic Acid