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The effects of dietary copper level on tissue activities of the copper containing superoxide dismutase (CuSOD) were investigated, and these activities related to those of other copper containing enzymes particularly cytochrome oxidase. Male weaning rats were fed a basal diet (containing 0.8 mg Cu/kg) or this diet supplemented with 4 or 24 mg Cu/kg. After 6 weeks, rats fed the basal diet were then repleted using the high copper diet. In the two copper supplemented groups, no differences were observed in any of the parameters measured. In these groups, tissue activities of CuSOD were in the order of liver > kidney > RBC > testis > heart > brain > lung > muscle. In the basal group, CuSOD activity decreased in liver, RBC and heart to 14, 25, and 61%, respectively, of control activities after 6 weeks' depletion; tissues other than brain or muscle showed smaller but significant changes. Conversely, heart and muscle cytochrome oxidase activities decreased to 30 and 45% of control activity and liver to 70%. With repletion, CuSOD activities in liver and heart increased more rapidly than did cytochrome oxidase activities. It is concluded that liver CuSOD activity, which is normally high, is greatly reduced with little change in cytochrome oxidase activity; the reverse is found for heart and muscle tissue. The relevance of these changes to the maintenance of tissue integrity is discussed. J. Nutr. 109: 1570-1576, 1979.

Four Border-Leicester × Merino wethers were used in a 4 × 4 Latin square experiment to study the effects of dietary sulphur on selenium absorption and retention. The basal diet contained 0.05% S and sodium sulphate was added to give additional treatment levels of 0.11, 0.17 and 0.24% total sulphur. Sodium selenate was added to all diets to bring the dietary selenium level to a constant 0.25 mg/kg. One hundred µCi 75Se as sodium selenate (specific activity 50 µCi/mg Se) was administered to the rumen per fistulam after a 10-day period of adjustment on each diet. Radioactivity in blood, urine, faeces and rumen digesta was measured at intervals over the succeeding 7 days. Twenty percent of the total activity in the rumen fluid was in the TCA supernatant fraction after 3 hours, and this proportion tended to increase slightly as sulphur intake increased. Fecal excretion of selenium accounted for between 44 and 51% of the dose after 7 days, the high levels being associated with increasing sulphur intake. However, these differences were not significant. Urinary excretion of selenium accounted for between 12% (0.05% S) and 22% (0.24% S) of the dose after 7 days, with treatment differences being significant. Levels of radioactivity in blood were significantly higher in sheep fed the 0.05% S diet compared with those fed the higher levels. The results show that sulphur affects apparent selenium excretion and suggest that the metabolism of these two elements is intimately related.

Presents several letters to the editor on topics and articles discussed in previous issues. Need to raise issues of the war, and the peace above the level of party politics; Use of the Nazi indoctrination of German youth by Nazi dictator Adolf Hitler; Publication of letters of indignant protest against the sickening radio advertising; Comments of Michael Straight in the January 4, 1943 issue on chance of the American restoration in Burma; Opinion of E.P. Osgood, of Reno, Nevada, on concern of liberals to the Beveridge Plan; Receipt of a pamphlet by the Michigan Manpower Mobilization Corps describing the organization.