| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1996: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1995: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Dietary zinc deficiency affects the growth and decreases the level of serum insulin-like growth factor-1 (IGF-1). We investigated the relationship between zinc and IGF-1 levels in rats. Wistar rats were randomly distributed into three groups : zinc-deficient, pair-fed or ad libitum-fed dietary treatments (Day0). Blood samples of each groups were collected from tail vein at Day 0,7,14,21 and body weight, naso-anal length, and the amount of food intake were measured. The growth of zinc-deficient group was markedly retarded and the amount of food intake in zinc-deficient group was decreased to 55% of ad-libitum group. Serum zinc level in zinc-deficient group gradually decreased and was not detected at day 21. IGF-1 level gradually increased until Day 14 in ad-libitum group but didn't increase in other groups. The correlation between zinc and IGF-1 level at Day 14 was seen. (r^2=0.467, P<0.05) Zinc concentration of liver, kidney, skeletal muscle and bone were measured at Day 21 in ad-libitum and zinc-deficient groups. In only bone tissue of zinc-deficient group, zinc concentration was low compared with ad-libitum group. Serum levels of zinc closely influenced the growth associated with IGF-1. On the other hand, IGF-1 level in pair-fed group decreased because of malnutrition. In zinc-deficient group, both zinc deficiency and malnutrition influenced the growth retardation. It is necessary to investigate the influence of zinc on the expression of IGF-1mRNA by cultured hepatocyte furthermore.
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