Eight wether lambs were used to determine effects of an oestradiol-17β (E2β) implant on metabolic responses to an epinephrine challenge. Blood was sampled before and after an epinephrine challenge, on days 0 and 22 of E2p implantation.Oestradiol-17 ft implants increased pre-injection (basal) serum insulin (INS), growth hormone and free fatty acids (FFA), and decreased basal serum urea nitrogen. After 21 days of E2Pimplantation, total concentrations of FFA decreased and INS increased in response to the epinephrine challenge compared with pre-implantation values. It is concluded that E2/3 implants alter metabolic responses to an epinephrine challenge in wether lambs.