Biochemical defect in chick lung resulting from copper deficiency.

Lung tissue from groups of chicks raised 23 d on diets deficient in copper had a higher proportion of 0.15 M NaCl-extractable collagen but lower aldehyde-reacting compounds and elastin than controls the same age. Although the lungs from deficient chicks weighed less, the ratio of lung to body weight for the two groups stayed relatively constant throughout the 23-d period. Lysyl oxidase activity in lungs of deficient chicks was strongly suppressed. Feeding the deficient chicks the diet with copper supplements restored lysyl oxidase activity in lung. This showed the close and specific control of lung lysyl oxidase by copper. The impairment in cross-linking through lysyl oxidase failure is implied from these studies. Clearly, copper is needed for the normal development of lung.