Antioxidant activity of melatonin in diabetes in relation to the regulation and levels of plasma Cu, Zn, Fe, Mn, and Se in Zucker diabetic fatty rats.
OBJECTIVE
To study the antioxidant activity of melatonin in diabetes in relation to the regulation and levels of plasma copper (Cu), zinc (Zn), iron (Fe), manganese (Mn), and selenium (Se) in Zucker diabetic fatty (ZDF) and lean (ZL) rats.


METHODS
At 6 wk of age, both ZDF (n = 30) and ZL (n = 30) animals were subdivided into three groups: control (C) (n = 10), vehicle (V) (n = 10), and melatonin-treated (M) (10 mg/kg/d; n = 10) rats for a 6-wk period. At the end of treatment period, plasma mineral levels were measured by flame (Cu, Zn, and Fe), electrothermal (Mn), and hydride generation (Se) atomic absorption spectrometry.


RESULTS
ZDF rats had significantly higher Cu, Fe, and Mn plasma levels than did ZL rats (P < 0.05). No significant differences were found between control and vehicle groups (P > 0.05). Melatonin treatment did not influence plasma levels of these antioxidant minerals (Cu, Zn, Fe, and Mn) in ZDF groups (M-ZDF versus C-ZDF group) and ZL (M-ZL versus C-ZL group) rats with the exception of Zn, whose mean plasma level was lower in the M-ZL versus C-ZL group. However, plasma Se levels increased significantly (P < 0.05) after melatonin supplementation in both groups (M-ZDF and M-ZL).


CONCLUSIONS
The higher mean plasma Cu, Fe, and Mn levels in the ZDF group are related to the enhanced oxidative stress in diabetes and obesity. Melatonin administration significantly enhanced plasma Se levels in both groups (M-ZDF and M-ZL). This is the first study to report that melatonin treatment increases plasma Se levels.
Department of Nutrition and Food Science, School of Pharmacy, University of Granada, Granada, Spain. nalarcon@ugr.es
Miguel
M
Navarro-Alarcon
Francisco J
FJ
Ruiz-Ojeda
Rosa M
RM
Blanca-Herrera
Ahmad
A
Agil
D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology*; D003300:Copper / Q000097:blood; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D019587:Dietary Supplements; D007501:Iron / Q000097:blood; D008297:Male; D008345:Manganese / Q000097:blood; D008550:Melatonin / Q000378:metabolism / Q000494:pharmacology*; D008903:Minerals / Q000097:blood; D009765:Obesity / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D011924:Rats, Zucker; D012643:Selenium / Q000097:blood*; D014131:Trace Elements / Q000097:blood*; D015032:Zinc / Q000097:blood
D000975:Antioxidants; D008903:Minerals; D014131:Trace Elements; D008345:Manganese; D003300:Copper; D007501:Iron; D012643:Selenium; D015032:Zinc; D008550:Melatonin