Relationship between insulin's haemodynamic effects and insulin-mediated glucose uptake.
BACKGROUND
Insulin resistance and hyperinsulinaemia are associated with hypertension. The relationship between insulin's metabolic and haemodynamic actions has not been fully elucidated however.


METHODS
We investigated, using the euglycaemic clamp technique, the relationship between insulin-mediated glucose uptake and insulin-induced changes in leg blood flow and cardiac index in 13 healthy subjects. As insulin's effects on blood flow are time dependent, studies were performed during a 4-h insulin (50 mU kg-1 h-1) infusion period.


RESULTS
Mean arterial pressure during insulin infusion increased (82.9 +/- 6.7 to 89.8 +/- 7.7 mmHg; P < 0.001), whereas heart rate was unaltered. Leg blood flow gradually increased from 1.09 +/- 0.57 to 1.47 +/- 0.67 mL min-1 dL-1 during the second hour, and to 1.65 +/- 0.68 mL min-1 dL-1 during the fourth hour of the clamp (P = 0.01). Stroke volume index increased from 56.5 +/- 13.3 to 63.7 +/- 16.3 mL m-2 (P = 0.004) and cardiac index from 3.42 +/- 1.02 to 3.73 +/- 1.05 L min-1 m-2 (P = 0.04). The insulin-mediated glucose disposal and the increases in leg blood flow were not correlated during the second hour (r = 0.21, P = 0.51) but showed a strong correlation during the fourth hour of the clamp (r = 0.88, P < 0.001). Insulin-mediated glucose disposal was not correlated with the increases in cardiac index.


CONCLUSIONS
Thus, insulin-mediated muscle blood flow may be an important contributor to glucose uptake during sustained exogenous hyperinsulinaemia aiming at physiological insulin levels.
ter Maaten
J C
JC
University Hospital, Vrije Universiteit, Amsterdam, The Netherlands.
Voorburg
A
A
de Vries
P M
PM
ter Wee
P M
PM
Donker
A J
AJ
Gans
R O
RO
D000328:Adult; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique; D006439:Hemodynamics / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D007866:Leg / Q000098:blood supply; D008297:Male; D012039:Regional Blood Flow / Q000187:drug effects; D013318:Stroke Volume / Q000187:drug effects; D013997:Time Factors
D001786:Blood Glucose; D007328:Insulin; D005947:Glucose