The effects were investigated of a 25-minute inhalation of
halothane with
oxygen on three to four months old pigs of the Large White breed. Symptoms of
malignant hyperthermia did not occur. The actual total
anesthesia, which causes slight
hypoproteinemia,
hypoglycemia and hypocholesterolemia without significant changes in the content of non-
esterified fatty acids (
NEFA) and
urea, induced only a slight increase of circulating
11-hydroxycorticosteroids (11-OHCS). The combination of
anesthesia with
castration of gilts or barrows significantly increased the concentration of 11-OHCS but did not reach the level recorded after the application of
ACTH. The higher levels of 11-OHCS were accompanied by higher concentrations of
NEFA and
glucose. The treatment of the animals lasting half an hour prior to inhalation of
halothane at maximum doses or one hour in the control unanesthetized pigs produced an effect, mainly on the 11-OHCS concentration and on the activity of
creatine kinase in the plasma. The results indicate that the adrenocortical response to the effect of
halothane is not stronger than the response to simple handling connected with excitement and muscular activity of the animals. Therefore there is no reason of considering
halothane anesthesia as
a factor causing great stress and pigs which in its course do not respond with
malignant hyperthermia as animals insensitive to stress. The aptness of denotation of clinical manifestations of genetically defective muscles in pigs is discussed.