Energy sources mobilization during muscular exercise in pregnant rats.

The experiments were carried out on three groups of female Wistar rats: nonpregnant rats (NP), rats pregnant for 10 days (P-10) and rats pregnant for 19 days (P-19). The rats were exercised on a treadmill set at 10 degrees incline at a running speed of 1200 m/h. Measurements were made at rest, after 30 min exercise, and after exercise till exhaustion. It was shown that in P-10 group the ability for the exhaustive exercise and metabolism of energy substrates during exercise were similar to those in NP group. The ability for exhaustive exercise of P-19 rats was reduced by 54.6% vs. NP rats. During exercise in P-19 group mobilization of glycogen in skeletal muscles was accelerated, mobilization of liver glycogen was impaired and hypoglycemia developed earlier than in NP group. Plasma FFA level in P-19 group reached a peak already after 30 min of exercise. Plasma triglyceride level was reduced during exercise in NP and P-10 groups but not in P-19 group. The level of triglycerides in skeletal muscle of each group was reduced during exercise but in P-19 group it returned to the resting level after the exhaustive exercise.