Decreased circulating levels of active ghrelin are associated with increased oxidative stress in obese subjects.
OBJECTIVE
To investigate the relationship between active ghrelin and oxidative stress in obese subjects.


METHODS
We measured the plasma levels of free 8-epi-prostaglandin F(2alpha) (8-epi-PGF(2alpha), a reliable and systemic marker of oxidative stress) and the active form of ghrelin in 17 obese and 17 normal subjects. The biologically active forms of ghrelin were measured using a commercially available radio-immunoassay kit and free 8-epi-PGF(2alpha) was measured using an enzyme immunoassay kit.


RESULTS
The circulating level of active ghrelin was significantly decreased (20.4 +/- 2.6 vs 40.9 +/- 3.9 fmol/ml, P < 0.01) while that of 8-epi-PGF(2alpha) was significantly increased (61.5 +/- 9.6 vs 17.3 +/- 3.4 pg/ml, P < 0.01) in obese subjects compared with normal subjects. The plasma levels of active ghrelin and 8-epi-PGF(2alpha) were significantly correlated in obese (r = -0.507, P < 0.05) and in all (r = -0.577, P < 0.01) subjects. Multivariate analysis showed that the plasma levels of active ghrelin and 8-epi-PGF(2alpha) were significantly and independently correlated in all subjects (F = 7.888, P < 0.01).


CONCLUSIONS
There is an inverse correlation between circulating levels of active ghrelin and oxidative stress in obesity. Low circulating levels of active ghrelin may enhance oxidative stress and the process of atherosclerosis in obese subjects.
Suematsu
Mina
M
Department of Internal Medicine, Division of Diabetology and Endocrinology, Mie University School of Medicine, Tsu, Mie, Japan.
Katsuki
Akira
A
Sumida
Yasuhiro
Y
Gabazza
Esteban C
EC
Murashima
Shuichi
S
Matsumoto
Kazutaka
K
Kitagawa
Nagako
N
Akatsuka
Hajime
H
Hori
Yasuko
Y
Nakatani
Kaname
K
Togashi
Kenji
K
Yano
Yutaka
Y
Adachi
Yukihiko
Y
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology; D001823:Body Composition / Q000502:physiology; D002784:Cholesterol / Q000097:blood; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood; D005260:Female; D054439:Ghrelin; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D015999:Multivariate Analysis; D009765:Obesity / Q000097:blood*; D018384:Oxidative Stress / Q000502:physiology*; D036361:Peptide Hormones / Q000097:blood*; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D054439:Ghrelin; D007328:Insulin; D036361:Peptide Hormones; D014280:Triglycerides; C075750:8-epi-prostaglandin F2alpha; D002784:Cholesterol; D015237:Dinoprost