title: Effect of early life stress on pancreatic isolated islets' insulin secretion in young adult male rats subjected to chronic stress.
abstract: Early stressful experiences may predispose organisms to certain disorders, including those of metabolic defects. This study aimed to explore the effects of early life stress on pancreatic insulin secretion and glucose transporter 2 (GLUT2) protein levels in stressed young adult male rats. Foot shock stress was induced in early life (at 2 weeks of age) and/or in young adulthood (at 8-10 weeks of age) for five consecutive days. Blood samples were taken before and after stress exposure in young adult rats. At the end of the experiment, glucose tolerance, isolated islets' insulin secretion, and pancreatic amounts of GLUT2 protein were measured. Our results show that early life stress has no effect on basal plasma corticosterone levels and adrenal weight, either alone or combined with young adulthood stress, but that early life + young adulthood stress could prevent weight gain, and cause an increase in basal plasma glucose and insulin. The homeostasis model assessment of insulin resistance index did not increase, when the rats were subjected to early life stress alone, but increased when combined with young adulthood stress. Moreover, glucose tolerance was impaired by the combination of early life + young adult stress. There was a decrease in islet's insulin secretion in rats subjected to early life stress in response to 5.6 mM glucose concentration, but an increase with a concentration of 16.7 mM glucose. However, in rats subjected to early life + young adulthood stress, islet's insulin secretion increased in response to both the levels of glucose concentrations. GLUT2 protein levels decreased in response to early life stress and early life + young adulthood stress, but there was a greater decrease in the early life stress group. In conclusion, perhaps early life stress sensitizes the body to stressors later in life, making it more susceptible to metabolic syndrome only when the two are in combination.
authors.affiliation: Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Forouzan
authors.initials: F
authors.lastname: Sadeghimahalli
authors.forename: Roxana
authors.initials: R
authors.lastname: Karbaschi
authors.forename: Homeira
authors.initials: H
authors.lastname: Zardooz
authors.forename: Fariba
authors.initials: F
authors.lastname: Khodagholi
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Rostamkhani
mesh_terms: D000367:Age Factors; D000818:Animals; D003345:Corticosterone / Q000097:blood; D005951:Glucose Tolerance Test; D051273:Glucose Transporter Type 2 / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013315:Stress, Psychological / Q000378:metabolism*
chemical_list: D051273:Glucose Transporter Type 2; D007328:Insulin; C495683:Slc2a2 protein, rat; D003345:Corticosterone