Biol. Pharm. Bull. 28(12) 2296—2301 (2005)

of bone and connective tissues and their maintenance is well established. There is also much evidence from human and animal studies that a lack of this mineral will lead to improper bone formation and bone fractures in newborns, infants, and sometimes even in adults. This is because the enzyme lysyl oxidase, which mediates the final step in the synthesis of collagen, a constituent of bone and connective tissue, is a copper-dependent enzyme. Thus the role of the trace element copper in the metabolism of bone and connective tissue is profound and inadequate copper nutrition may be an important factor in the etiology of osteoporosis. Copper deficiency in milk-fed infants induces the development of severe bone demineralization and a lack of ossification of growth centers. These symptoms are dramatically alleviated through the daily oral administration of copper 800 mg/kg of body weight. This impairment of proper bone formation and growth may result from the effects of copper deficiency on the lysyl oxidases that are involved in bone metabolism. The effects of orally administered copper, however, have not been fully clarified. The present study therefore was undertaken to determine the effects of copper administration in animals with adequate copper nutrition in vivo.