Question

9. The enzyme PEPCK is unique to gluconeogenesis (not part of glycolysis). Mice with higher than normal levels of PEPCK in the muscle (PEPCKMUS) were created characterized. Compare the lactate levels of the 2 types of mice. Why do you think there's such a difference? TABLE 2 Metabolic parameters of PEPCK-cmus mice and controls after strenuous exercise Values are the means - S.D., for the number of mice shown in the parenthesis. The VO2 (oxygen consumption), VO2max (maximal VO2), VCO2 (carbon dioxide production), VCO2max (maximal CO2 production), and RER were determined as described under "Experimental Procedures.", p < 0.05. Variables VO2 at rest(ml.kg .min) VCO2 at rest (ml.kg .min) RER (VCO2/02) at rest Blood lactate at rest (mm) VO2max (ml.kg .min) VCO2 at VO2max (ml.kg .min-?) RER at VO2max Blood lactate (mm) after exercise Wild type PEPCK-cmus n=10 n=9 46.9 + 9.6 47.7 10.9 37. 3 9 .34 40.9 14.1 0.79 +0.05 0.77 0.05 4.90 +0.34 3.70 +0.17 112. 3 20.9 156.4 8.06 110.8 21.0 142.0 18.48 0.99 +0.08 0.91 +0.03 8.12 : 5.0 3.70 1.00*

Answer 1

When we exercise our body uses oxygen to break down glucose for energy. During intense exercise there may not be enough oxuoxy available to complete the process so a substance called lactate is produced. But this lactate or lactic acid can build up in your blood stream faster than you can burn it off. So the lactate levels of two mice are different.