Early life overfeeding and its effects on hypothalamic-pituitary-adrenal and sympatho-adrenal-medullary axes.

Introduction: Overweight and obesity is becoming more and more common in Australia. The percentage of obesity in children has increased every year. Obese children in a particular are considered more likely to become obese in adulthood, which leads to a higher risk of developing short and long-term health problems and behaviours, such as Type 2 diabetes, cardiovascular disease and the response to stress. Hypothesis: Neonatal nutrition programs development of the hypothalamic-pituitary-adrenal (HPA) axis and sympatho-adrenal--medullary (SAM) axis.<br><br> Aim: 1. To determine how the HPA axis is altered in male rats by neonatal overfeeding. 2. To determine how the HPA axis is altered in female rats by neonatal overfeeding. 3. To investigate if neonatal overfeeding makes an animal more susceptible to the effects of a high fat diet. 4. To determine how the adrenal catecholamine response to Lipopolysaccharide (LPS) is altered by neonatal overfeeding. Results: The neonatally overfed male and female rats are heavier than their normal weight counterparts throughout the juvenile phase and into adulthood. The male and female rats have hyper-responsive HPA axes to LPS challenge, but there are sex differences in the mechanisms for this. Neonatal overfeeding also programs some changes in brainstem responses to LPS, while susceptibility to high fat diet remains relatively unaffected. Summary: We suggest that avoiding overfeeding in earlier life may help in reducing the risks of HPA axis dysfunction throughout life. We also identify two potential targets for pharmacological treatments to reduce HPA axis inefficiency in the neonatally overfed.