Serum levels of cortisol , adrenocorticotropic hormone ( ACTH ) , endothelin-1 ( ET-1 ) , tumor necrosis factor - ( TNF - ) , interleukin-6 ( IL-6 ) and C-reactive protein ( CRP ) were measured by standard ELISA and radioimmunoassay before anesthesia ( Ta ) , at the end of the surgery ( Tb ) and 1 day after the surgery ( Tc ) .