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Exercise adaptation responses for gastric inhibitory polypeptide (GIP) and insulin in obese children. Possible
Insights
Exercise training in obese children unexpectedly increased gastric inhibitory polypeptide (GIP) secretion and improved insulin sensitivity, demonstrating a novel uncoupling of GIP and insulin responses.
Area of Science:
- Pediatric Endocrinology
- Metabolic Syndrome Research
- Exercise Physiology
Background:
- Obesity in children is linked to metabolic dysfunction, including impaired glucose and insulin regulation.
- Previous studies suggest calorie restriction improves glucose utilization with decreased insulin and GIP secretion.
Purpose of the Study:
- To investigate the effects of a 5-month exercise training program (ETP) on glucose, insulin, and GIP responses in obese children.
- To explore the relationship between exercise-induced metabolic changes and hormonal secretion.
Main Methods:
- A mixed meal test was administered to obese children before and after a 5-month ETP, alongside matched controls.
- The ETP involved aerobic exercise sessions and modest dietary restrictions, increasing caloric expenditure.
- Measurements included glucose, insulin, and gastric inhibitory polypeptide (GIP) levels at fixed intervals.
Main Results:
- Obese children showed an increased GIP response post-ETP compared to pre-ETP and controls.
- Insulin levels were lower post-ETP, indicating improved insulin tolerance, though still higher than controls.
- Glucose tolerance remained unchanged, but glucose utilization improved, associated with increased GIP secretion.
Conclusions:
- Exercise training in obese children leads to increased GIP secretion and improved insulin sensitivity, uncoupling GIP and insulin responses.
- This contrasts with findings from calorie restriction studies.
- Results suggest GIP may influence peripheral tissue sensitivity to insulin-induced glucose uptake.
Abstract:
Thirteen obese children and matched controls were fed a mixed meal, and responses were evaluated at fixed intervals for glucose, insulin, and gastric inhibitory polypeptide (GIP). The obese children were evaluated before and within 48 h after completion of a 5-mo exercise training program (ETP). The ETP included three aerobic exercise sessions per week and modest diet restrictions. Caloric expenditure was increased by approximately 300 kcal/exercise session. Weight gain was minimal over the 5 mo. An unexpected increase in GIP response and improved insulin tolerance were recorded for the obese children post-ETP. GIP values were higher (P less than 0.05) at 30 and 60 min and led to a highly significant elevation (P less than 0.01) of the integrated GIP response for post-ETP obese versus both pre-ETP and normal-weight controls. Insulin values were lower (P less than 0.05) at 30 and 60 min and led to a lower integrated insulin response (P less than 0.0585) for post-ETP obese children. However, the obese children continued to secrete more insulin (P less than 0.05) than normal-weight controls. Glucose tolerance, similar for pre-ETP obese subjects and controls, did not change in post-ETP children. Exercise-induced improvement in glucose utilization in these obese children was associated with an increase in GIP secretion. This contrasts with reports that calorie restriction will improve glucose utilization with decreased insulin and GIP secretion. The study demonstrates a previously unreported uncoupling of GIP and insulin secretion and suggests shifts in peripheral tissue sensitivity to insulin-induced glucose uptake. These shifts may, in part, be influenced by GIP.