Adrenal medullary overactivity in lean, borderline hypertensive young men.
BACKGROUND
There may be a link among stress, adrenal medullary activation, and the development of hypertension. Obesity is characterized by sympathetic activation and predisposes to hypertension, but may be associated with low or normal adrenal medullary activity. We hypothesized that plasma epinephrine (E) levels and adrenal medullary responsiveness to mental stress are lower in overweight than in lean borderline hypertensive subjects.


METHODS
We compared groups of lean (n = 62) and overweight (n = 29) borderline hypertensive young men as well as lean (n = 36) and overweight (n = 7) normotensive young men from the same population. Plasma catecholamines and heart rate (HR) were measured at rest during a hyperinsulinemic glucose clamp and during mental arithmetic-induced stress.


RESULTS
Plasma norepinephrine (NE) and E, HR, and responses to stress were increased in borderline hypertensive subjects. Our results showed that NE was increased only in lean borderline hypertensive subjects at rest, but in overweight subjects as well during stress, with DeltaNE being similar in lean and overweight subjects. We found that E was higher in lean than in overweight borderline hypertensive subjects at rest and during stress (both P <.001), as were DeltaE and DeltaHR (both P <.05). Independent of BP status, body mass index was negatively related to E during stress (P <.01) and waist circumference negatively related to resting E (P <.001) and DeltaHR (P =.02).


CONCLUSIONS
Sympathetic neural activity and responsiveness are increased in borderline hypertensive young men, but measures of overweight are independently related to lower plasma E and HR responses. We suggest that adrenal medullary activation in borderline hypertension mainly characterizes lean subjects.
Reims
Henrik M
HM
Department of Cardiology, Ullevaal University Hospital, Oslo, Norway.
Fossum
Eigil
E
Høieggen
Aud
A
Moan
Andreas
A
Eide
Ivar
I
Kjeldsen
Sverre E
SE
D000293:Adolescent; D000307:Adrenal Gland Diseases / Q000097:blood / Q000503:physiopathology*; D000313:Adrenal Medulla / Q000378:metabolism / Q000503:physiopathology*; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000503:physiopathology*; D007328:Insulin / Q000378:metabolism; D008297:Male; D009638:Norepinephrine / Q000097:blood; D009664:Norway / Q000453:epidemiology; D009765:Obesity / Q000097:blood / Q000503:physiopathology; D012044:Regression Analysis; D012146:Rest; D013223:Statistics as Topic; D013315:Stress, Psychological / Q000097:blood; D013851:Thinness / Q000097:blood / Q000503:physiopathology*
D015415:Biomarkers; D001786:Blood Glucose; D007328:Insulin; D009638:Norepinephrine