Fig. 1.

Food intake, body weight, plasma albumin concentration and oxidized/reduced ratio of plasma albumin in rats fed protein-restricted diets. Rats were fed experimental diets containing 20% (20C group, n = 7, closed circles), 10% (10C group, n = 6, open circles), 5% (5C group, n = 6, open squares) or 3% (3C group, n = 6, open triangles) casein. Dietary intake (A) and body weight (B) were measured during the experimental period. Blood was drawn from the tail vein every week. Plasma albumin concentrations were monitored (C). The percentages of MA (D), NA-1 (E) and NA-2 (F) within total albumin were analyzed by HPLC. HPLC was performed using an ES-502N ion-exchange column with an increasing ethanol concentration from 0% to 10% in 50 mM sodium acetate and 400 mM sodium sulfate buffer (pH 4.85). Values represent the mean ± SEM. Means not sharing the same letter are significantly different from each other (p<0.05). Typical HPLC profiles of plasma albumin from rats fed a 10% (G) or 5% (H) casein diet for 2 weeks are shown. The plasma cyst(e)ine concentration at 2 weeks after the start of the experiment were analyzed by an amino acid analyzer (n = 3) (I).