Insulin resistance in essential hypertension.

Area of Science:

• Metabolic Research
• Cardiovascular Science
• Endocrinology

Background:

• High blood pressure (hypertension) is frequently observed in individuals with obesity and diabetes, conditions often characterized by insulin resistance.
• The relationship between hypertension and insulin resistance, independent of obesity and glucose intolerance, requires further investigation.

Purpose of the Study:

• To determine if essential hypertension is associated with insulin resistance in individuals without obesity or glucose intolerance.
• To investigate the specific pathways of glucose metabolism affected by insulin resistance in hypertension.

Main Methods:

• Utilized the euglycemic insulin-clamp technique to measure insulin sensitivity.
• Employed [3H]glucose isotope dilution to assess glucose turnover.
• Conducted indirect calorimetry to determine whole-body glucose oxidation in 13 young subjects with untreated essential hypertension and 11 age- and weight-matched controls.

Main Results:

• Subjects with essential hypertension exhibited markedly impaired total insulin-induced glucose uptake compared to controls (3.80 +/- 0.32 vs. 6.31 +/- 0.42 mg/min/kg, P < 0.001).
• The defect in glucose uptake was primarily attributed to reduced nonoxidative glucose disposal (glycogen synthesis and glycolysis) (1.19 +/- 0.24 vs. 3.34 +/- 0.44 mg/min/kg, P < 0.001).
• Total glucose uptake was inversely and significantly correlated with both systolic and mean blood pressure (r = 0.76, P < 0.001).

Conclusions:

• Essential hypertension appears to be an insulin-resistant state, independent of obesity and glucose intolerance.
• The observed insulin resistance in hypertension is specific to glucose metabolism, localized in peripheral tissues, and affects nonoxidative pathways.
• The severity of insulin resistance in hypertension is directly correlated with the degree of blood pressure elevation.