Differences of glucose metabolism between adipose tissue and skeletal muscle in the early stage of catch-up growth in rats and its mechanism / 中华内分泌代谢杂志

ABSTRACT

Objective To observe the glucose utilization in adipose tissue and skeletal muscle during catch-up growth, and to explore the mechanism of catch-up growth of adipose tissue. Methods Male Wistar rats were randomly divide into normal control group(NC)and catch-up group(RN). Rats in RN group received 50%of food consumed by NC group for 4 weeks, then were re-fed spontaneously as the rats in NC group. In the end of the fifth week(NC1 group and RN1 group)and the sixth week(NC2 group and RN2 group), the experiment was performed. [3]-2-deoxy-glucose was used for detecting the glucose uptake rate. RT-PCR and Western-blot were used for detecting the levels of mRNA and membrane protein of glucose transporter-4(Glut4). Results The glucose uptake rates in adipose tissue and skeletal muscle of RN1 group increased by 189.6%(P<0.01)and reduced by 36.5%(P<0.05)respectively, as compared with NC1 group. After 2 weeks of catch-up growth, the glucose uptake rates in adipose tissue of RN2 group increased by 157.3%(P<0.01)and decreased by 41.5%(P<0.05) in skeletal muscle as compared with NC2 group. However. no significant difference in Glut4 mRNA levels in muscle or in adipose tissue between NC and RN groups were found. The membrane protein of GIut4 after insulin-stimulating in RN1 group and RN2 group reduced by about 46.5%(P<0.01)and 32.1%(P<0.05)in muscle and increased by 116.5%(P<0.01)and 89.9%(P<0.01)in adipose tissue respectively. Conclusion There exists the redistribution of glucose from skeletal muscle to adipose tissue during the early stage of catch-up growth, which results in the catch-up growth of adipose tissue. This change is induced by the tissue-specific alteration of insulin-stimulated Glut4 protein translocation.