Interaction of aluminum with zinc and copper and its effects on pituitary-testicular axis: a histological study.

To elucidate the interactions between aluminum and certain essential trace metals, an experiment was performed on rats fed diets with suboptimal or optimal levels of zinc or copper. Half of each group of animals were fed the same diet but with 1000 ppm aluminum added. Changes were noted after 120 days. Severe testicular damage was seen in rats fed either the low zinc or the low copper diet. The lesions included a wide range of spermatogenic cell degeneration and tubular atrophy. When aluminum was added to the diet, the testicular destruction of Zn-deficient rats was significantly reduced. This indicated that the presence of aluminum in the diet protected the testis against the damage caused by zinc deficiency. Pituitary glands were examined. Hypertrophy of basophiles was more pronounced in rats fed the suboptimal zinc or copper diet. When aluminum was added to their diet, the changes were reversed. The mechanisms by which aluminum protects male gonadal functions against Zn deficiency are discussed. This study is the first to demonstrate the preventive effect of aluminum against testicular damage caused by zinc deficiency.