Effects Of Swimming Training And The "Yi-qi & Bu-shen" Kind Of Chinese Medicine On Serum Testosterone Level In Rats--A Study Of Several Factors On Their Possible Mechanisms Influencing Testosterone Biosynthesis In Testis

Many studies demonstrate that long-term intensive training can lead body to several pathological or physiological changes, including disturbance of endocrine system, usually shows that low level of serum testosterone induced by strenuous exercises, which is one of the reasons of poor performance and delayed fatigue-eliminating. The methods of fast recovery of physical ability and prevention and cure the generation of low level of serum testosterone are regarded more and more by sports medicine community. Researchers have a relatively consistent opinion on occurrence mechanism of low level of serum testosterone after long-term high intensity training or overreaching, they considered that the principal reason of low-level serum testosterone induced by exercise was that functions of several levels in hypothalamus-pituitary-gonad axis (HPGA) are suppressed. The regulation of testosterone biosynthesis by HPGA is accomplished through several steps including translocation of cholesterol substrates and enzyme-catalyzing reactions at last. However, the possible mechanisms on these levels remain unclear.For many years it was the activity of the P450scc enzyme, which is located on the matrix side of the inner mitochondrial membrane, in converting cholesterol to pregnenolone that was considered as the rate-limiting step in steroidogenesis. However, a number of observations have discovered that the activity and amount of the P450scc enzyme are unaffected by trophic hormone stimulation when learned during the acute time frame of minutes to a few hours, an interval during which large quantities of steroids can be synthesized. It later became clear that the true rate-limiting step regulated by hormone stimulation was the delivery of the substrate cholesterol to the mitochondrial membrane and to the P450scc- Many studies demonstrated that de novo protein synthesis is absolutely needed in the hormone regulated, acute production process of steroids. This protein is responsible fortransferring the cholesterol substrates to the inner mitochondrial membrane and the P450scc enzyme system. Along with the development of technologies of molecular biology and biochemistry, steroidogenic acute regulatory protein (StAR) is confirmed to be such indispensable protein plays in regulation of steroid hormone biosynthesis.In order to probe into the effects of endurance training on StAR and related rate-limiting enzymes in producing testosterone, and exploring an effective Chinese medicine compound for preventing and curing low-level serum testosterone, a Wistar rat model of intensive training with increasing load by degrees was conducted. 50 male Wistar rats were randomly divided into 4 groups as follows: (1)sedentary control group (SC), (2)Sedentary + Medicine group (SM), (3)Endurance Training group (ET), (4)Endurance Training + Medicine group (EM). The rats underwent 6 weeks of swimming training. After drawing materials, the ultrastructural changes of Leydig cells was studied by morphometry, the concentration of total testosterone and corticosterone were tested by radioimmunoassay, and the gene expression of StAR, P450scc, 11P-HSD in testis as well as AR in deep quadriceps femoris were measured by RT-PCR.The results indicated that: endurance training could induce the decrease of serum testosterone and thus impair physical performance. Accompanied with the decline of volume density of lipid droplets in Leydig cells, the reduction of StAR and P450scc gene expression at mRNA level may responsible for the low-level serum testosterone after long-term intensive exercise. The consequence of serum corticosterone concentration and 11p-HSD mRNA levels suggest that they may be not involved in exercise-induced low-level serum testosterone. Through reducing the structural damage of Leydig cells and improving StAR and AR mRNA level, Chinese medicine compound of "invigorating 'qi' and tonifying the kidney" could be an effective means to prevent and cure the generation of low-level serum testosterone during strenuous training and thus maintain t...