Lesions produced by copper deficiency in neonate and older rats.

I . Three groups of rats of different mean weights were given a diet of milk treated with hydrogen sulphide and supplemented with copper-free minerals and vitamins. Also divided into three groups of similar weights were rats given the same diet supplemented with 500 pg Culweek and stock rats which were given a commercial diet. 2. In a second experiment eight adult female rats were given the Cu-deficient diet for z weeks before mating and during pregnancy, and in a third experiment were mated and immediately after mating were given the Cu-deficient diet or the Cu-supplemcnted diet. 3. Cu deficiency reduced the growth rate of younger rats but had a much less marked effect on the weight of more mature rats. Achromotrichia appeared at 5 weeks; diarrhoea, with the faeces frequently containing undigested blood, and subcutaneous oedema were terminal changes. Deaths occurred in the youngest group of rats after g weeks and later in heavier, older rats. 4. Histological changes were seen in livers, spleens, testes and epididymes but not in blood vessels or bones. 5. Pups were not born to mothers given the deficient diet before mating, and the pups from mothers given the deficient diet only during pregnancy were born dead or showed congenital abnormalities. 6. Foetal and liver Cu concentrations for the various groups of animals are given. 7. Maintenance of the foetus appears to be the biological process most susceptible to Cu deficiency in the rat.