成長期ラット唾液腺における亜鉛酵素の性質に関する研究

Abstract

Zinc (Zn) has been known to be an essential metal and is very important for growth and cell division. Zn is required for activities of more than 300 enzymes. In our previous studies, we used rats to study the effect of low intakes of zinc and calcium on the growth and development in tibia metaphysis. However we have no report on the enzyme for cofactor zinc in rats. Twenty, three-week-old male Wistar rats were divided into groups and randomly given a diet containing different levels of zinc (adequate Zn level 34.4ppm), high-Zn diet (Zn level 51.4ppm), low-Zn diet (14.7ppm), and Zn-deficiency (Zn level 3.7ppm) for 6 weeks. We examined the properties of the enzyme for cofactor zinc enzyme (alkaline phosphatase and Cu, Zn superoxide dismutase) in serum, liver and salivaly glands. 1. Serum concentrations of Zn did not show a significant difference among the four groups. 2. In the high-Zn and low Zn diet groups, alkaline phosphatase activity in serum and liver was increased in conparison to the control group, however, in submandibular glands and sublingual glands it was decreased as compared with the control group. 3. The Cu, Zn-superoxide dismutase activity in liver did not show a significant difference among the four groups. In the low-Zn and Zn deficiency diet groups, the type of Cu, Zn-Super oxide dismutase activity in submandibular glands was decreased as compared with the control group ; on the other hand, in the high-Zn, low-Zn and Zn deficiency diet groups, Cu, Zn-superoxide dismutase activity in sublingual glands and parotid glands was decreased as compared with the control group. These results suggested that the enzyme activities of alkaline phosphatase and type of Cu, Zn-superoxide dismutase were not dependent on the level of zinc present in the diet of each of the four groups, particularly under normal physiological zinc levels.