Treadmill walking differently affects body composition and metabolic parameters of female rats from normal or small litters.

This work assessed whether walking affects bodily development and metabolic parameters of female rats raised in small litters (three pups, group S) or control litters (nine pups, group C). After weaning, some of the rats had five sessions per week of a 30-min treadmill walking (CE and SE), while the others remained sedentary (CS and SS) until the age of 120 days. Exercise caused a reduction of body weight (CS/CE = 1.18), Lee index (CS/CE = 1.04), fasting blood glucose (CS/CE = 1.35), mesenteric (CS/CE = 1.23), and ovarian fat (CS/CE = 1.33) in CE, but only glucose was decreased in SE (SS/SE = 1.16). The diameter of adipocytes decreased to a half in the small-litter groups. Exercise increased subcutaneous (CS/CE = 0.88 and SS/SE = 0.71), but decreased retroperitoneal adipocytes (CS/CE = 1.2 and SS/SE = 1.3). Litter size reduction had little impact on females at the age of 120 days, but the light physical activity seemed insufficient to counteract all the effects of lactational overfeeding. On the other hand, pups from exercised mothers had a decrease in their biometric and glycemic indexes, demonstrating the transgenerational action of regular, although light, exercise.

Exercise partially reverses the inhibitory effect of caffeine on liver gluconeogenesis in type 1 diabetic rats with hypoglycemia.

The purpose was to determine the possible effects of exercise and/or caffeine on hypoglycemia and liver gluconeogenesis in diabetic rats. These were divided into four subgroups: (a) intraperitoneal insulin only, (b) exercise bout before insulin, (c) caffeine after insulin, and (d) exercise bout before and caffeine after insulin. The marked glycemic drop 45 min after insulin (0 min = 229.00, 45 min = 75.75) was considerably reduced (p < 0.05) by caffeine or exercise (45 min: exercise = 127.00, caffeine = 104.78). However, this systemic effect was lost (p > 0.05) when they were combined (45 min: exercise + caffeine = 65.44) (Mean, in mg·dL-1). Caffeine alone strongly inhibited liver glucose production from 2 mM lactate 45 min after insulin (without caffeine = 3.05, with caffeine = 0.27; p < 0.05), while exercise + caffeine partially re-established the liver gluconeogenic capacity (exercise + caffeine = 1.61; p < 0.05 relative to the other groups) (Mean, in µmol·g-1). The improved hypoglycemia with caffeine or exercise cannot be explained by their actions on liver gluconeogenesis. As their beneficial effect disappeared when they were combined, such association in diabetic patients should be avoided during the period of hyperinsulinemia due to the risk of severe hypoglycemia.