title: Inhibitory effect of a two day fast on reactive oxygen species (ROS) generation by leucocytes and plasma ortho-tyrosine and meta-tyrosine concentrations.
abstract: ABSTRACT Since glucose intake acutely increases reactive oxygen species (ROS) generation by polymorphonuclear leucocytes (PMN) and mononuclear cells (MNC), we have now investigated whether a fast over a period of 48h reduces ROS generation by these cells. Eight normal subjects were fasted for 48h. Blood samples were obtained at 0, 24h and 48h. ROS generation by PMN fell significantly at 24h (66.1 +/- 19.5% of basal) and further at 48h (45.9 +/- 23.0 % of basal; p < 0.001). ROS generation by MNC fell to 62.4 +/- 16.5% at 24h and by 48.4 +/- 16.5% (p < 0.001) by 48h. The level of p47(phox) subunit, an index of NADPH oxidase, the enzyme converting molecular oxygen to superoxide (O(.)(2)(-)) radical, also fell in parallel. Plasma o-tyrosine/phenylalanine ratio fell significantly from 0.326 +/- 0.053 mmol/mol to 0.303 +/- 0.055 mmol/mol at 48h and m-tyrosine/phenylalanine ratio fell from 0.363 +/- 0.063 mmol/mol to 0.340 +/- 0.064 mmol/mol (p < 0.05). Thus, a 48h fast may reduce ROS generation, total oxidative load and oxidative damage to amino acids.
authors.affiliation: Division of Endocrinology, State University of New York at Buffalo and Kaleida Health, Buffalo, New York 14209, USA.
authors.forename: P
authors.initials: P
authors.lastname: Dandona
authors.forename: P
authors.initials: P
authors.lastname: Mohanty
authors.forename: W
authors.initials: W
authors.lastname: Hamouda
authors.forename: H
authors.initials: H
authors.lastname: Ghanim
authors.forename: A
authors.initials: A
authors.lastname: Aljada
authors.forename: R
authors.initials: R
authors.lastname: Garg
authors.forename: V
authors.initials: V
authors.lastname: Kumar
mesh_terms: D000328:Adult; D005215:Fasting / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism*; D019255:NADPH Oxidases; D009504:Neutrophils / Q000378:metabolism*; D009994:Osmolar Concentration; D010649:Phenylalanine / Q000097:blood; D010750:Phosphoproteins / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013997:Time Factors; D014443:Tyrosine / Q000097:blood*
chemical_list: D010750:Phosphoproteins; D017382:Reactive Oxygen Species; D014443:Tyrosine; D010649:Phenylalanine; C026741:2-tyrosine; C015566:3-tyrosine; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1