Abstract. In a long term experiment laboratory mice were selected for high (line DU-hTP) or low (line DU-ITP) paternal treadmill Performance to differentiate the endurance fitness. In generation 54 six enzymes and seven Substrates were investigated in the blood plasma of males and females in DU-hTP (n = 104) and DU-ITP (n = 141). Compared with line DU-ITP in line DU-hTP significantly higher enzyme activities, increased glucose concentration and lower level of triglycerides were found. The components of total cholesterol were divergent between the two lines and positively effected in DU-hTP for higher HDL-cholesterol. Animals with high endurance fitness showed a higher gain in the HDL-cholesterol concentration with increased total cholesterol level in the blood than gain of LDL + VLDL-cholesterol concentration.