Sympathetic activity and response to ACE inhibitor (enalapril) in normotensive obese and non-obese subjects.
BACKGROUND
Angiotensinogen has been proposed as a possible link between obesity and hypertension because the adipocyte produces angiotensinogen and contains the enzymes required for its conversion. Moreover, sympathetic overactivity has been reported in obese subjects. The aim of this study was to compare heart sympathetic activation and serum angiotensinogen levels in obese and non-obese normotensive subjects, their relationship, and the effect of a drug that modifies the renin-angiotensin system.


METHODS
Serum angiotensinogen, leptin, lipids, glucose, and insulin levels were measured and 24-h electrocardiograph monitoring was carried out in 41 (20 non-obese and 21 obese) volunteers before and after administration of 5 mg enalapril twice/day for 7 days.


RESULTS
Obese subjects had higher values than non-obese subjects for % body fat (35.1+/-4.6 vs. 30.5+/-5.2; p=0.005), triglycerides (1.93+/-0.9 vs. 1.25+/-0.7 g/L, p=0.002), insulin (114.8+/-82.5 vs. 45.9+/-22.2 pmol/L), leptin (31.4+/-20.4 vs. 14.1+/-11.2 ng/mL, p=0.002), and LF/HFn index (4.3+/-2.9 vs. 2.2+/-1.3, p<0.005). Enalapril increased angiotensinogen levels only in the non-obese group (4.2+/-3.9 vs. 9.7+/-5.4 ng/mL, p=0.001) and diminished the LF/HFn index (4.3+/-2.9 vs. 3.0+/-1.4, p=0.007) in the group of obese subjects. There was no association between angiotensinogen levels and sympathetic activity.


CONCLUSIONS
Higher level of sympathetic activity was found in normotensive obese as compared with non-obese subjects. Enalapril treatment reduced heart sympathetic activity in obese subjects but did not change angiotensinogen levels.
Amador
Norma
N
Unidad de Investigación en Epidemiología, Instituto Mexicano del Seguro Social (IMSS), León, Guanajuato, Mexico.
Guizar
Juan-Manuel
JM
Malacara
Juan-Manuel
JM
Pérez-Luque
Elva
E
Paniagua
Ramón
R
D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000808:Angiotensinogen / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects*; D001823:Body Composition; D004656:Enalapril / Q000494:pharmacology*; D006321:Heart / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D007328:Insulin / Q000378:metabolism; D020738:Leptin / Q000097:blood; D008055:Lipids / Q000097:blood; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000502:physiology
D000806:Angiotensin-Converting Enzyme Inhibitors; D001786:Blood Glucose; D007328:Insulin; D020738:Leptin; D008055:Lipids; D000808:Angiotensinogen; D004656:Enalapril