Histochemical Studies of Alkaline Phosphatase in Epiphyseal Cartilage of Normal and Zinc-deficient Chicks

Abstract

The object of this study was to compare histochemically the distribution of alkaline phosphatase, mucopolysaccharides and collagen in the epiphyseal plates of normal chicks, zinc-deficient chicks and zinc-deficient chicks fed histamine or indomethacin. A diet based on isolated soybean protein was used and manganesedeficient chicks were studied for comparison. Alkaline phosphatase in normal chick epiphysis was found in the proliferating cells near the maturing region, in maturing cells, and in degenerating cells which contained remnants of cellular elements. Little or no alkaline phosphatase was present in early proliferating cells or in fully degenerated cells, but it was again found in calcifying areas. The epiphyseal plate cells of zinc-deficient chicks showed this normal progression of alkaline phosphatase activity only if they were near blood vessels or in areas of calcification, where proximity to blood vessels had no effect and normal alkaline phosphatase activity was found. In the deficient chick, cells remote from blood vessels were much delayed in their development of alkaline phosphatase. No difference in distribution of mucopolysaccharides or collagen was found. The epiphysis from zinc-deficient chicks fed histamine or indomethacin showed the same distribution of alkaline phosphatase as did zinc-deficient tissue even though these agents grossly moderated the leg defect. Manganese deficiency did not affect the distribution of alkaline phosphatase in chick epiphyseal tissue. Alkaline phosphatase in noncalcifying chick epiphyseal plate tissue appeared to be necessary for normal cell maturation and degeneration, processes which were defective in the zinc-deficient chicks. This and other theories about alkaline phosphatase function are discussed.