title: Corticotropin-releasing factor--induced adrenocorticotropic hormone release in the sheep fetus: blockade by cortisol.
abstract: We administered intravenous injections of synthetic ovine corticotropin-releasing factor to chronically cannulated sheep fetuses and monitored fetal plasma adrenocorticotropic hormone and cortisol concentrations. The three doses of corticotropin-releasing factor used (10, 100, or 1000 ng X kg-1) increased fetal plasma adrenocorticotropic hormone; fetal plasma cortisol levels rose with the highest dose of corticotropin-releasing factor. Administration of corticotropin-releasing factor at these concentrations did not change fetal heart rate or blood pressure. Elevation of fetal plasma cortisol levels to 40 to 80 ng X ml-1 by infusions of the steroid blocked the adrenocorticotropic hormone responses to all three doses of corticotropin-releasing factor. These data indicate that corticotropin-releasing factor can increase plasma adrenocorticotropic hormone concentrations in the late-gestation fetus and that these increases can be blocked by elevations in fetal plasma cortisol levels within a physiologic range. This suggests that cortisol modulates adrenocorticotropic hormone release by the fetal pituitary gland late in gestation.
authors.forename: J C
authors.initials: JC
authors.lastname: Rose
authors.forename: B Y
authors.initials: BY
authors.lastname: Hargrave
authors.forename: P M
authors.initials: PM
authors.lastname: Dix
authors.forename: P J
authors.initials: PJ
authors.lastname: Meis
authors.forename: M
authors.initials: M
authors.lastname: LaFave
authors.forename: B
authors.initials: B
authors.lastname: Torpe
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000378:metabolism*; D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure; D003346:Corticotropin-Releasing Hormone / Q000502:physiology*; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005318:Fetal Heart / Q000502:physiology; D005333:Fetus / Q000502:physiology*; D006339:Heart Rate; D006854:Hydrocortisone / Q000097:blood / Q000502:physiology*; D011247:Pregnancy; D012756:Sheep
chemical_list: D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone