Corticosteroid-binding globulin, cortisol, free cortisol, and sex hormone-binding globulin responses following oral glucose challenge in spinal cord-injured and able-bodied men.

Circulating cortisol, corticosteroid-binding globulin, and sex hormone-binding globulin were measured retrospectively in plasma samples following the oral glucose tolerance test in 20 spinal cord-injured men and 20 able-bodied controls. Plasma-free cortisol responses attenuated more rapidly in the able-bodied men, compared to spinal cord-injured subjects, due to significant rise in circulating corticosteroid-binding globulin whereas changes in total plasma cortisol were similar in both groups. The changes in plasma-free cortisol in both groups paralleled changes in insulin and glucose and show that spinal cord-injured men had heightened exposure to free cortisol during this dynamic test. This raises the possibility that the mechanism of abdominal obesity and the propensity towards insulin resistance in spinal cord-injured men could be subtly mediated by perturbations in free cortisol. There were no significant changes in plasma sex hormone-binding globulin in either group.