Effect of selenium on plasma glucose of rats: role of insulin and glucocorticoids

The effects of acute treatment (i.p.) of selenium (Se) on glucoregulation and on plasma levels of glucose, insulin and corticosterone were determined in both fed and 24-hour-fasted rats. In this experiment animals were treated with saline (control) or 1.3, 1.6 and 3.8 mg/kg doses of Se. Blood samples were collected before, 30, 60 and 90 min following injection. The results obtained show that acute intraperitoneal (i.p.) administration of Se (1.6 mg/kg or more) causes hyperglycemia in rats. It was found that Se does not change levels of plasma insulin in either fasted or fed animals. Se did, however, significantly increase the plasma levels of corticosterone in all Se-treated groups. In order to confirm the role of corticosterone and thus support the significance of adrenal glands in this hyperglycemic response, animals were subjected to bilateral adrenalectomy. Blood samples were collected before, 30, 60 and 90 min following intraperitoneal treatment with Se. The results indicate that bilateral adrenalectomy abolishes the hyperglycemic response to Se. It can be concluded that adrenal glands play a role in Se-induced hyperglycemia. The increase in corticosterone levels suggest the possibility of gluconeogenesis in contributing to this hyperglycemic response.