Introduction
During the past 20 years there has been much
emphasis on detecting and treating hypertension,
which is an important risk factor for cardiovascular
disease,' and several large scale trials have shown that
a reduction in blood pressure is associated with a
decrease in cardiovascular morbidity and mortality.2-5
Some of the drugs used to treat hypertension, however,
have adverse effects, including disturbances of serum
lipid concentrations and glucose metabolism.5"7 Treatment
with thiazide diuretics and f3 blockers has been
associated with an increased incidence of impaired
glucose tolerance6 and diabetes.57 Few attempts have
been made, however, to evaluate specific influences of
pharmacological treatment of hypertension on glucose
metabolism-for example, to determine whether it
decreases secretion of insulin or sensitivity to insulin,
or both. Sensitivity%to insulin may be important as
studies have shown that hypertension is accompanied
by resistance to instin.8J10
We evaluated the effect of long term treatment with
two widely used PI3 adrenergic blockers, metoprolol
and atenolol, on glucose disposal mediated by insulin
and examined their effects on glucose, insulin, and
lipid metabolism.