Relationship between plasma renin profile and leptinaemia in patients withessential hypertension

Both leptin and the renin-angiotensin system (RAS) can influence the activi ty of the sympathetic nervous system, water and electrolyte metabolism as w ell as vascular remodelling, which are all involved in the regulation of ar terial blood pressure. Thus leptin and the RAS may act together in the path ogenesis of essential hypertension. The present study aimed to answer the f ollowing question: does an interrelationship exist between leptinaemia and the plasma renin activity (PRA) profile in normotensive and hypertensive su bjects? Forty-three patients with essential hypertension (EHP) (23 females, 20 males, mean age 39.0 +/- 1.8 years, mean body mass index (BMI) 26.8 +/- 0.6 kg/m(2), mean arterial pressure (MAP) 123 +/- 2 mm Hg) and 32 healthy subjects (NTS) (18 females, 14 males, mean age 38.6 +/- 2.2 years, mean BMI 25.4 +/- 0.5 kg/m(2), MAP 95 +/- 1 mm Hg) were examined. Plasma leptin lev els were estimated once after the administration of a diet containing 100-1 20 mmol Na/day and after overnight 8-h recumbency. PRA was estimated twice: first after the administration of a diet containing 100-120 mmol Na day an d overnight 8-h recumbency (PRA I), and a second time after 3 days of sodiu m restriction (20 mmol Na/day), and 3 h of upright position (PRA II). Antih ypertensive drugs were withdrawn 7 days before the study. In EHP plasma lep tin concentration was insignificantly higher than in NTS (14.0 +/- 2.0 vs 1 0.8 +/- 1.5 ng/ml respectively). Only females with hypertension showed a si gnificant positive correlation between plasma leptin concentrations (expres sed as the logarithmic values) and PRA I. Using the multiple regression ana lysis, in all studied subjects (EHP and NTS together), logarithm (log) of p lasma leptin concentrations was significantly related to gender, BMI and MA P. Multiple regression analysis performed separately for EHP or NTS reveale d a significant relation of log plasma leptin concentrations with gender an d BMI. A significant correlation was found between log leptinaemia values a nd BMI, mean and systolic blood pressure respectively if the whole group of subjects (EHP+NTS) or EHP and NTS separately were analysed. Especially in hypertensive women a highly significant correlation was found between log p lasma leptin concentrations and MAP. We conclude that a significant relatio nship between leptinaemia and PRA does exist in females with EH and that pa rticipation of both PRA and leptin in the pathogenesis of EH in females see ms to be likely.