Insulin levels are similar in obese salt-sensitive and salt-resistant hypertensive subjects.
Evidence supports the hypothesis that hyperinsulinemia, especially in obesity, contributes to salt-sensitive hypertension by enhancing sodium retention and blunting the normal reduction of sympathetic drive and vascular resistance that occurs during a high versus low NaCl diet. To address these issues, we studied 18 obese (body mass index, > 27 kg/m2) subjects younger than 45 years old with mild hypertension to determine if the salt-sensitive versus salt-resistant subset had higher insulin levels, retained more volume, and failed to suppress sympathetic drive and vascular tone normally on a high (approximately 200 mEq/d) versus low (20 mEq/d) NaCl diet for 7 days each. Six obese subjects were salt sensitive, with an 8.4 +/- 2.1 (SEM) mm Hg increase of ambulatory mean blood pressure on the high versus low NaCl diet. Ten obese subjects were salt resistant, with a 7.1 +/- 0.9 mm Hg reduction of ambulatory mean blood pressure on high versus low NaCl. The salt-sensitive and salt-resistant groups had similar values, respectively, for the insulin area under the curve during an oral glucose tolerance test on low (14.6 +/- 1.8 versus 14.0 +/- 1.4 mU x min/dL, P = NS) and high (10.6 +/- 1.5 versus 10.6 +/- 1.0, P = NS) salt diets. Although insulin levels were similar, insulin raised calf blood flow in salt-resistant subjects (P < .05) but not in salt-sensitive subjects on the high NaCl diet.(ABSTRACT TRUNCATED AT 250 WORDS)
Egan
B M
BM
Department of Medicine, Medical College of Wisconsin, Milwaukee.
Stepniakowski
K
K
Nazzaro
P
P
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D002302:Cardiac Output / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D007328:Insulin / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D012964:Sodium / Q000652:urine; D012982:Sodium, Dietary / Q000494:pharmacology*; D014655:Vascular Resistance / Q000187:drug effects
D007328:Insulin; D012982:Sodium, Dietary; D012964:Sodium