The influence of anaesthesia on the concentrations of progesterone and cortisol in peripheral blood plasma of sheep.

Levels of progesterone and cortisol were measured in the peripheral plasma of sheep subjected to barbiturate (sodium pentobarbitone) and gaseous (halothane) anaesthesia both alone and in combination. Significant increases were recorded inthe level of cortisol in all experiments and in the levels of progesterone in all experiments except that involving halothane alone. It was also found that the cortisol levels remained elevated for a greater period of time than those of progesterone.