Leptin and norepinephrine plasma concentrations during glucose loading in normotensive and hypertensive obese women

We performed this study to investigate whether changes in plasma glucose, i nsulin, and norepinephrine concentrations during an oral glucose tolerance test (OGTT) are associated with changes in plasma leptin levels in normoten sive and hypertensive obese women. Plasma insulin, glucose, norepinephrine, and leptin concentrations were evaluated at the baseline and during OGTT i n normotensive women (NT-Ob, N = 24, mean age 38.3 +/- 1.8 years, body mass index [BMI] 37.9 +/- 1.1 kg/m(2)) and hypertensive (HT-Ob, N = 25, mean ag e 37.7 +/- 1.9 years, BMI 39.4 +/- 1.3 kg/m(2)) obese women, and in a group of normal-weight women (controls, N = 20, mean age 38.3 +/-: 1.3 years, BM I 23.1 +/- 0.4 kg/m(2)). The OGTT caused a significant increase in plasma l eptin concentrations in both NT-Ob and HT-Ob groups, whereas no such change was detectable in control subjects. Area under curve (AUC) for plasma lept in showed a direct correlation with norepinephrine AUC in both NT-Ob (r = 0 .73, P = .001) and HT-Ob (r = 0.74, P = .001) group, which was still detect able in multivariate analysis (P = .014 and P = .017, respectively). Our st udy confirms that glucose loadings increases circulating leptin concentrati ons in obese women, and demonstrates the existance of an association betwee n leptin and norepinephrine changes during OGTT in both normotensive and hy pertensive obese women. We hypothesize that this association may reflect th e lack of leptin suppression by catecholamines or a direct leptin-induced s ympathoactivation. These findings suggest that leptin could be relevant in the regulation of blood pressure in obese women. (C) 2001 American Journal of Hypertension, Ltd.