Endocrine Abstracts

Stress defined as a disruption in the normal homeostatic functions of an organism caused by a stressor (a physiological or psychological challenge) is an unavoidable experience of life. Previous studies suggest that stress hormones have acute adverse effects on glycaemic control. The aim of this study was to assess the effect of chronic psychological and physical stress on the expression of insulin receptor (INSR) and glucose transporter-4 (GLUT4) in male Sprague–Dawley rats.

Male rats (12 weeks old) were randomly distributed into 3 groups: control, water avoidance stress (WAS), forced swimming stress (FSS). The stress procedures were performed between 0900 and 1100 to minimize the effect of circadian rhythm and lasted for 28 consecutive days. Levels of insulin and corticosterone in the blood were determined using enzyme-linked immunosorbent assay. Glucose metabolism was assessed by glucose tolerance test (GTT) and insulin tolerance test (ITT), and expression of INSR and GLUT4 in skeletal muscle. Food intake and final body weight were also measured.

The FSS rats had decreased food intake as well as final body weight; and without adverse changes in GTT, stress worsened insulin sensitivity in FSS rats and increased serum insulin level. Stress also increased corticosterone, decreased INSR and GLUT4 in the skeletal muscle of both groups. In conclusion, chronic stress impairs insulin sensitivity and alters glucose metabolism through the down-regulation of INSR and GLUT4 in skeletal muscles.