Effects of halothane and methoxyflurane on the hypothalamic-pituitary-adrenal axis in rat.
Effects of acute exposure (2 h) to either 1.5% halothane or 0.5% methoxyflurane on chemical mediators of the hypothalamic-pituitary-adrenal (HPA) axis were evaluated in male Sprague-Dawley rats immediately after exposure, after the righting reflex (4 h), or 24 h postexposure. Effects of these anesthetics on hippocampal corticotropin releasing factor (CRF) were also evaluated. Methoxyflurane caused significant elevations in pituitary adrenocorticotropin hormone (ACTH)-like immunoreactivities in all three of the experiment's time groups, yet halothane failed to cause the same response immediately after exposure. Serum ACTH-like immunoreactivities were significantly elevated immediately after exposure to both anesthetics, but were not elevated at 4 and 24 h postexposure. Corticosterone (CORT)-like immunoreactivities were significantly elevated by halothane in all experimental groups, and in the 2- and 24-h groups following methoxyflurane exposure. Hippocampal CRF-like immunoreactivities remained unaffected by either anesthetic. Results indicate that a 2-h exposure to either halothane or methoxyflurane results in significant activation of the rat hypothalamic-pituitary-adrenal axis, and that the activation appears to be sustained over a 24-h period.
Karuri
A R
AR
Department of Biomedical Sciences, Tufts University School of Veterinary Medicine, North Grafton, MA, USA.
Engelking
L R
LR
Kumar
M S
MS
D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000378:metabolism; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D003345:Corticosterone / Q000097:blood; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D006221:Halothane / Q000494:pharmacology*; D006624:Hippocampus / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D008733:Methoxyflurane / Q000494:pharmacology*; D010902:Pituitary Gland / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000187:drug effects* / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley
D018685:Anesthetics, Inhalation; D008733:Methoxyflurane; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006221:Halothane; D003345:Corticosterone