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Early postnatal hypothalamic-pituitary-adrenal axis activity and reduced insulin sensitivity in adult rats



Objective. Early life stress influences the development of metabolic disorders, including functional changes in the developing of pancreas mediated hypothalamic-pituitary-adrenal (HPA) axis. In the present study, the role of an early postnatal stress on corticosterone, glucose, and insulin levels was investigated during young adulthood.

Methods. Two groups of pups were studied, including control group (pups not receiving foot shock by communication box), and early stress group (pups receiving foot shock by communication box 2 times/day for 5 consecutive days). In rats, concentration of plasma corticosterone, glucose, and insulin was detected before and after placing them into the communication box at 2 weeks of age. At 8–10 weeks of age, concentrations of plasma corticosterone, glucose, and insulin and glucose tolerance were measured in young adult rats.

Results. Our results showed that early postnatal foot shock stress increased the corticosterone, insulin, and glucose levels in the postnatal age (p<0.01) that did not last until young adult age, but it caused a significant increase in plasma glucose and insulin levels (p<0.05) following the intraperitoneal glucose tolerance test (IPGTT) in young adult rats.

Conclusions. These results suggest that impaired IPGTT in young adult rats who experienced early postnatal stress can indicate insulin resistance or reduced insulin sensitivity that make it at risk of the type 2 diabetes later in life.