Effects of high-fat diet induced obesity on tissue zinc concentrations and zinc transporter expressions in mice / 한국영양학회지

ABSTRACT

PURPOSE: Obesity is often associated with disturbances in the mineral metabolism. The purpose of this study was to investigate the effects of high-fat diet-induced obesity on tissue zinc concentrations and zinc transporter expressions in mice. METHODS: C57BL/6J male mice were fed either a control diet (10% energy from fat, control group) or a high-fat diet (45% energy from fat, obese group) for 15 weeks. The zinc concentrations in the serum, stool, and various tissues were measured by inductively coupled plasma (ICP)-atomic emission spectrophotometry or ICP-mass spectrophotometry. The levels of zinc transporter mRNAs in the liver, duodenum, and pancreas were measured by real-time RT-PCR. The levels of serum adipokines, such as leptin and IL-6, were determined. RESULTS: The total body weight, adipose tissue weight, and hepatic TG and cholesterol concentrations were significantly higher in the obese group, as compared to the control group. The obese group had significantly higher levels of serum leptin and pro-inflammatory IL-6 concentrations, and had significantly lower levels of serum alkaline phosphatase activity. The zinc concentrations of the liver, kidney, duodenum, and pancreas were all significantly lower in the obese group than in the control group. On the other hand, the fecal zinc concentrations were significantly higher in the obese group than in the control group. The serum zinc concentrations were not significantly different between the two groups. The ZnT1 mRNA levels of the liver and the pancreas were significantly higher in the obese group, as compared to the control group. Hepatic Zip10 mRNA was also increased in the obese group. CONCLUSION: Our study findings suggest that obesity increases fecal zinc excretion and lowers the tissue zinc concentrations, which may be associated with alterations in the zinc transporter expressions.