Glucose Transport MRNA Expression In The Scale Less Carp Is Modulated During Spawning Migration

The scale-less carp resides in the alkaline (pH 9.1-9.5) and saline waters (9‰ total salinity) of Lake Qinghai, which is located, at an elevation of 3,200 m above sea level, on the Tibetan plateau of Qinghai-province in western China. Unlike most stenohaline cyprinids, G. przewalskii undergo an annual spawning migration between the saline lake water and freshwater rivers.Because it can produce more ATP to use glucose, animal will use glucose as energy substance in advanced. The first step of glucose metabolism is to pass membrane. Glucose transporters (GLUTs) are members of a structurally related family of membrane glycoproteins that facilitate cellular uptake of glucose. So it is important to investigate the expression of GLUT in different tissues to find the specialty of scale-less carp under hypoxia and salinity changes.This study demonstrated that the expression of GLUT mRNAs in the scale-less carp muscle, heart, liver and brain changed during hypoxia and in different aquatic surrounding, using northern-blot. In addition, we tested the concentration of glycogen, lactate, pyruvate and ATP in the muscle and liver.The resμlts are as followed:1. Hypoxia caused a change in glut mRNA, especially there being an initial significant increase during 8 hour to 24 hour.2. after hypoxia, the concentration of glycogen ,ATP and PCr was markedly decreased in muscle. The concentration of glucose and lactate was increase. In liver, the concentration of glycogen was decrease and the lactate was increase, the level of glucose is maintained.3. In lake water and salt water (same Na+ concentration as lake), the GLUT mRNA was decrease markedly. The concentration of glycogen was increase in liver.Those data suggest that:1. Hypoxia stimμlates GLUT mRNA expression in muscle, liver, heart, brain ofscale-less carp.2. Scale-less carp can response hypoxia immediately. The glycogen was analyzed to fulfil the needs of glycolysis.3. It was the salinity rather than magnesium causing the metabolism and mortality in the scale-less carp.