Study on the influence of vitamin A on IGF-1 concentration of iodine excess mice

Abstract

Objective To observe the influence of vitamin A （VA） on liver Insulin like Growth Factors 1 （IGF-1） expression of iodine excess mice. Methods Kunming mice were randomly divided into six groups： normal （I- 50 μgg/L,VA 4000 U/kg）, HI（I- 3000 μgg/L,VA 4000 U/kg）, low VA（I- 50 μgg/L,VA 0 U/kg）, HI ＋ low VA（I- 3000 μgg/L,VA0 U/kg）, HI ＋ VAI （I- 3000 μgg/L,VA 8000 U/kg） and HI ＋ VA2（I- 3000 μgg/L,VA 16 000 U/kg） group. ELISA was used to measure the concentration of serum IGF-I and RT-PCR to measure the expression level of liver IGF-1 mRNA 3 and 6 months afterwards. Results In the 6th months, the serum IGF-I level of HI, low VA and HI ＋ low VA group decreased obviously compared with that of the normal group（q = 3.52,3.29,3.84,P 〈 0.05）, VA supplement increased the level of IGF-1 to some extent between normal and HI group. Liver IGF-1 mRNA expression level of HI and low VA group showed a decreasing tendency compared with that of the normal grouμg while it increased in HI ＋ VA groups in the period of the first 3 months, but kept unchanged later on. Conclusions The iodine excess inhibits the liver secreting IGF-1 in mice, which is partly antagonized by VA supplement. Key words: Iodine; Vitamin A; Insulin like growth factors 1