Insulin Sensitivity, Leptin, Adiponectin, Resistin, and Testosterone in Adult Male and Female Rats After Maternal-Neonatal Separation and Environmental Stress
AJP Regulatory Integrative and Comparative Physiology
Published online on September 06, 2017
Abstract
Care of premature infants often requires parental and caregiver separation particularly during hypoxic and hypothermic episodes. We have established a neonatal rat model of human prematurity involving maternal-neonatal separation and hypoxia with spontaneous hypothermia prevented with external heat. Adults previously exposed to these neonatal stressors show a sex difference in the insulin and glucose response to arginine stimulation suggesting a state of insulin resistance. The current study used this cohort of adult rats to evaluate insulin resistance (Homeostatic Model Assessment of Insulin Resistance [HOMA-IR]), plasma adipokines (reflecting insulin resistance states), and testosterone. The major findings were that daily maternal-neonatal separation led to an increase in body weight and HOMA-IR in adult male and female rats and increased plasma leptin in adult male rats only; neither prior neonatal hypoxia (without or with body temperature control) nor neonatal hypothermia altered subsequent adult HOMA-IR or plasma adiponectin. Adult male-female differences in plasma leptin were lost with prior exposure to neonatal hypoxia or hypothermia; male-female differences in resistin were lost in the adults with prior neonatal hypoxia allowing spontaneous hypothermia Exposure of neonates to daily hypoxia while preventing spontaneous hypothermia led to a decrease in plasma testosterone in adult male rats. We conclude that neonatal stressors result in subsequent adult sex-dependent increases in insulin resistance and adipokines, and that our rat model of prematurity with hypoxia with the prevention of hypothermia alters adult testosterone dynamics.