title: Effect of melatonin on enzyme activities of glutathione reductase from human erythrocytes in vitro and from rat erythrocytes in vivo.
abstract: The in vivo and in vitro effects of melatonin on enzyme activity of glutathione reductase (Glutathione: NADP(+) oxidoreductase, EC 1.8.1.7; GR) were investigated in this study. Glutathione reductase was purified from human erythrocytes 5.823-fold with a yield of 24% by ammonium sulfate fractionation, affinity chromatography on 2',5'-ADP Sepharose 4B and gel filtration chromatography on Sephadex G-200. Enzyme activity was determined by the Calberg and Mannervik method using a spectrophotometer at 340 nm. For in vitro experiments, the enzyme activity increased at 0.02 mM and decreased at 0.08 mM melatonin concentration and reached a plateau above 0.08 mM. Melatonin was administered 10 mg/kg intraperitoneally (ip) and had a stimulatory effect on the enzyme. In vivo studies were performed for melatonin in Sprague-Dawley rats and time-dependent effects were demonstrated. Glutathione reductase activity in erythrocytes was increased more by melatonin at 1 and 3 h. These results indicate that pharmacological levels of melatonin increased enzyme activity in erythrocytes. They also indicate that melatonin may be pharmacologically useful in patients with a deficiency of the enzyme in red blood cells causing hemolytic anemia.
authors.affiliation: Biotechnology Application and Research Center, Ataturk University, Erzurum, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Erat
authors.forename: Mehmet
authors.initials: M
authors.lastname: Ciftci
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D004912:Erythrocytes / Q000201:enzymology*; D005980:Glutathione Reductase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000975:Antioxidants; D005980:Glutathione Reductase; D008550:Melatonin