Does leptin play a role in the pathogenesis of essential hypertension?

Background: Leptin is produced and released by adipocytes in proportion to fat stores. Leptin as an anorectic hormone plays an important role in the r egulation of food intake, energy expenditure, a nd insulin secretion. In co ntrast, neuropeptide Y, insulin, cortisol, and growth hormone are presumed to be appetite modulators. Leptin and neuropeptide Y are both involved in t he activation of sympathetic tone. Increased body fat stores in obese patie nts are involved in the pathogenesis of some metabolic disorders (e.g., hyp erinsulinaemia, glucose intolerance) and arterial hypertension. Methods and Results: Based on this pathophysiological background, we tried to assess t he relationship between plasma leptin and blood pressure in 41 patients wit h essential hypertension (EHP; 20 females, 21 males, mean age 38.7+/-1.9 ye ars, mean body mass index - BMI 25.8+/-0.5 kg/m(2)) and in an appropriately sex- and BMI-matched control group of 27 normotensive healthy subjects (NH S; 11 females, 16 males, mean age 39.7+/-2.5 years, mean BMI 24.8+/-0.6 kg/ m(2)). The plasma leptin concentration did not differ significantly between EHP and NHS (13.0+/-1.9 vs. 8.1+/-1.0 ng/ml, respectively). In both groups a significant positive correlation was found between BMI and plasma leptin concentration (p<0.0001). A significant positive correlation (p<0.02) was found between leptinaemia and mean (MAP), systolic and diastolic blood pres sures, if data were analyzed for all examined subjects or separately only f or women. Such a correlation could not be confirmed for male NHS and EHP su bjects. The plasma neuropeptide Y concentration was higher in EHP than in N HS (77.1+/-23.0 vs. 63.6+/-9.8 pg/ml, p = 0.05). In contrast to neuropeptid e Y plasma insulin, cortisol, and growth hormone concentrations were simila r in EHP and in NHS. Conclusion: Both EHP and NHS are characterized by a po sitive correlation between BMI and leptinaemia. Leptin may be indirectly in volved in blood pressure regulation, especially in women of both NHS and EH P.