Effect of dexamethasone on immunoreactive corticotropin-releasing factor in the rat median eminence and intermediate-posterior pituitary.
Immunoreactive ACTH (I-ACTH) concentrations in the anterior pituitary, intermediate-posterior pituitary (IP), and plasma and immunoreactive corticotropin-releasing factor (I-CRF) concentrations in the median eminence and IP were determined in rats receiving dexamethasone for various periods from 16 h to 10 days. Plasma I-ACTH concentrations were decreased 16 h after a single injection of dexamethasone. Anterior pituitary I-ACTH concentrations did not decrease until 4 days after the start of dexamethasone medication. IP I-ACTH concentrations did not change throughout these periods. I-CRF concentrations in median eminence and IP rapidly decreased after dexamethasone administration. These results raise the possibility that the source of I-CRF in the IP is hypothalamic.
D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000378:metabolism; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D003907:Dexamethasone / Q000494:pharmacology*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008473:Median Eminence / Q000187:drug effects / Q000502:physiology*; D010902:Pituitary Gland / Q000187:drug effects / Q000502:physiology*; D010904:Pituitary Gland, Posterior / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone