PLASMA ENDOTHELIN-1 LEVELS IN OBESE HYPERTENSIVE AND NORMOTENSIVE MEN

Plasma endothelin-l (ET-1) levels were studied in 15 obese hypertensiv e (mean age 48.5 +/- 3.9 years) and 15 obese normotensive men (mean ag e 49.5 +/- 3.6 years) before and after weight loss due to an 800 kcal/ day diet lasting 12 weeks. Circulating peptide concentrations were als o assessed in nonobese hypertensive (n = 11) and normotensive men (n = 12). Baseline plasma ET-1 levels were similar in obese hypertensive ( 0.87 +/- 0.22 pg/ml) and obese normotensive men (0.91 +/- 0.30 pg/ml). In seven obese hypertensive men, caloric restriction normalized blood pressure levels (systolic: from 166.6 +/- 8.1 to 145.0 +/- 6.3 mmHg, P < 0.0001; diastolic: from 106.6 +/- 5.1 to 89.1 +/- 2.0 mmHg, p < 0. 0001) and decreased body mass index (BMI) (from 33.4 +/- 1.6 to 29.6 /- 2.1 kg/m(2), P < 0.002) and plasma ET-L levels (from 0.93 +/- 0.21 to 0.64 +/- 0.26 pg/ml, P < 0.05). In the remaining obese hypertensive men (n = 8), blood pressure levels were not normalized by caloric res triction despite a significant decrease of BMI and plasma ET-1 levels (from 0.83 +/- 0.23 to 0.60 +/- 0.16 pg/ml, P +/- 0.04). Weight loss a lso significantly decreased BMI and ET-1 (from 0.91 +/- 0.30 to 0.65 /- 0.19 pg/ml, P +/- 0.01) in obese normotensive men. Baseline ET-1 an d fasting insulin levels were significantly correlated in obese hypert ensive (r = 0.518, P +/- 0.05) and obese normotensive men (r = 0.535, P < 0.04). Changes in fasting insulin levels correlated with correspon ding changes in plasma ET-1 levels after weight loss in both obese hyp ertensive Cr = 0.558, P < 0.04) and obese normotensive men (r = 0.596, P < 0.02). Moreover, plasma peptide levels were significantly higher (P < 0.02) in obese hypertensive and obese normotensive men than in no nobese normotensive men (0.58 +/- 0.28 pg/ml). In conclusion, this stu dy shows that plasma ET-I concentrations are increased in human obesit y. The increase could depend on fasting insulin concentrations, abnorm al peptide clearance, or both, Hypertension does Plasma not influence the behavior of plasma ET-1 levels in obese men.