Exercise training improves the metabolic phenotype of pre and postnatal growth restricted male rat offspring

Fetal growth restriction impairs glucose tolerance. We determined whether exercise training early or later in life normalizes the metabolic phenotype in adult male rats born small or postnatally growth restricted. Growth restriction induced on day 18 of pregnancy yielded growth Restricted (Restrict 10–15% smaller) compared to sham‐operated Control (Con) and sham‐operated Reduced litter (Red) pups. Male offspring were sedentary or underwent early (5–9 wks of age) or late (20–24 wks) exercise training (treadmill running 5 day/wk 60 min/day). A fasted ip glucose tolerance test (GTT 1g/kg) was performed 48 hrs after the last exercise bout at 9 or 24 wks. At 9 wks HOMA‐IR was not different between sedentary groups and was lower after early exercise in all groups, suggesting improved insulin sensitivity. At 24 wks Restrict and Red had higher HOMA‐IR compared to Con. First phase insulin secretion tended to be lowest in sedentary Restrict (75–85%) and increased with late exercise training in Restrict (80%). Despite normal glucose, late exercise Con had lower insulin during GTT compared to Con sedentary and early exercise while early exercise Red had lowered insulin compared to sedentary Red at 24wks. In summary early exercise improved adult insulin sensitivity in postnatal growth restricted rats. The 85% reduction in insulin secretion, associated with β‐cell mass deficits was restored with late exercise in males born small.