Effects of Exogenously Administered Cortisol on Lipolysis in the Common African Toad, Bufo regularis

Abstract

The role of cortisol on lipolysis in amphibians is not known. This study was designed to investigate the effects of cortisol on
lipolysis in the common African toad, Bufo regularis. Adult toads were collected and used for the study. The animals were fasted
24h and anaesthetized by sodium thiopentone 50mg/kg intraperitoneally. Blood was collected from truncus arteriosus for
estimation of blood glucose and blood free fatty acids levels. Cortisol caused significant increase in blood free fatty acids and
glucose levels in the common African toad. Pretreatment with prazosin 0.2mg/kg produced significant reduction in blood free
fatty acids but caused increase in blood glucose levels. Propranolol 0.5mg/kg pretreatment caused significant increase in blood
free fatty acids and significant reduction in glucose levels. The combination of both blockers abolished the cortisol-induced
hyperglycemia and caused significant reduction in blood free fatty acids. The results of this study confirmed that cortisol caused
lipolysis from toad adipose tissue. Thus, cortisol administration caused increase in blood free fatty levels and induced
hyperglycemia. The alpha-adrenergic receptors are involved in the release of free fatty acids in the common African toad Bufo
regularis.