Diabetes, Vol 25, Issue 4 268-274, Copyright © 1976 by American Diabetes Association
Vascular reactivity to angiotensin II and to norepinephrine in diabetic subjects
AR Christlieb, HU Janka, B Kraus, RE Gleason, EA Icasas-Cabral, LM Aiello, BV Cabral and A Solano
Vascular responsiveness to infused angiotensin II and to norepinephrine was
determined in 14 normal subjects and two groups of diabetic subjects, 16
with no clinically detectable diabetic complications and 14 with diabetic
retinopathy but no clinical evidence of nephropathy. All were maintained on
a 100-mEq. -Na- 100-mEq. -K diet. Serum electrolytes, 24-hour urinary
sodium, creatinine clearance, and plasma renin activity did not differ
significantly among the groups. Group mean baseline diastolic pressure in
those with retinopathy was higher than in normal subjects but no
significantly different from that of uncomplicated diabetics. The pressor
dose of angiotensin II (ng./kg./min. to increase diastolic blood pressure
20 mm. Hg) for each group respectively was 11.5 +/-0.9, 12.9+/- 1.3, and
8.3 +/- 1.3, and the slope of the dose-response curve (mm. Hg rise in blood
pressure resulting from the infusion of 1 ng./kg./min. following the
initial increment in blood pressure) was 2.0 +/-0.2, 1.6+/-0.2, 3.3+/- 0.6.
For norepinephrine, the pressor doses were 163 +/- 24, 212+/-21, and123 +/-
11 and slopes were 0.17 +/- 0.03, 0.13 +/- 0.02, and 0.20 +/-0.02. Neither
diabetic group differed significantly from normal subjects. Diabetics with
retinopathy were more sensitive to angiotensin II, pressor dose (P less
than 0.059) and slope (P less than 0.02), and to norepinephrine, pressor
dose (P less than 0.006) and slope (P =0.05) than those without
complications. These data suggest that vascular reactivity is enhanced in
diabetics with retinopathy.