Values are means ± SD. Significant differences after administration were

analyzed by using Student’s t-test (* P < 0.05). Figure 4 Effect of dietary carnosine and ß-alanine on the CN1 mRNA expression in the kidneys of male mice; 2 g/kg body weight of carnosine, ß-alanine, or water was orally administered to mice (n = 6–8). Values are means ± SD. Significant differences after administration were analyzed by using Student’s t-test (**P < 0.01). Discussion Carnosine synthase have been tried to purify from various sources [21–24] and Drozak et al. purified carnosine synthase from chicken pectoral muscle and the enzyme identified as ATPGD1, which is a member DAPT of the ATP-grasp family [20]. This paper was investigated about whether ATPGD1 involved in carnosine synthesis selleck chemicals llc in mice. Firstly, the tissue distribution of the ATPGD1 gene was investigated. The ATPGD1 gene was expressed more in brain and muscle than in olfactory bulbs, liver and kidney and particularly in the vastus lateralis muscle. The expression of the ATPGD1 gene was 1.6-fold

higher than that in the soleus muscle. The carnosine content in the vastus lateralis muscle (0.47 mmol/kg tissue) was higher than in the soleus muscle (0.35 mmol/kg tissue, P = 0.007, data not shown), indicating that the ATPGD1 mRNA level depends on the carnosine content. Secondly, we investigated the carnosine content and the expression of carnosine synthesis-related genes after the ingestion of carnosine or ß-alanine. The

carnosine supplementation group increased the carnosine content in blood and muscle and the expression of CN1 in the kidneys. Carnosine was injected into the tail vein of proton-coupled oligopeptide transporter PEPT2 knockout mice and the kidney/plasma concentration ratio of carnosine in the PEPT2 null mice was one-sixth that in wild-type [25]. Thus, it was considered that the ingested carnosine was eliminated from the serum by filtration into the urine and reabsorption into the kidney, and the reabsorbed carnosine increased Thalidomide the expression of CN1 in the kidney and would be hydrolyzed to ß-alanine. Carnosine and ß-alanine administration increased the ATPGD1 gene levels in the vastus lateralis muscles. This suggests that the hydrolyzed ß-alanine in kidney increased ATPGD1 gene expression. Recently, Baguet et al. investigated the expression of ATPGD1 mRNA in human skeletal muscle. Twenty omnivorous subjects were randomly divided into a vegetarian and a mixed diet group, and took part in a five-week sprint training intervention (2–3 times per week). The ATPGD1 mRNA expression in the vegetarian diet group was decreased to 60 % (P = 0.023) by five weeks of sprint training [26]. This is consistent with our result showing that ß-alanine is an important factor in ATPGD1 expression. Chronic chicken breast extract or ß-alanine supplementation leads to improved performance in high-intensity exercise [27, 28].