Control of ACTH and vasopressin in neurohypophysectomized conscious dogs.
Adrenocorticotropin (ACTH), cortisol, and vasopressin responses to clamped decreases in blood pressure (MAP) and to ovine corticotropin-releasing factor (CRF) infusion (20 ng X kg-1 X min-1) in intact and neurohypophysectomized (NHX) conscious dogs were examined. Mean arterial blood pressure was decreased 28 mmHg by a controlled infusion of sodium nitroprusside. Hypotension induced large increases in ACTH (peak 164 +/- 25 pg/ml), cortisol (peak 12.5 +/- 2.5 micrograms/dl), and vasopressin (peak 221 +/- 64 pg/ml) in intact (n = 7) dogs. NHX (n = 7) significantly attenuated these responses to hypotension. CRF infusion induced increases in ACTH similar in intact (n = 4) and NHX (n = 4) dogs. However, cortisol responses were significantly attenuated by NHX. Interestingly, CRF infusion induced small but significant increases in vasopressin from 3.0 +/- 1.1 to 8.1 +/- 2.0 pg/ml. We conclude that NHX attenuates ACTH and vasopressin responses to hypotension and cortisol responses to CRF-induced increases in ACTH. CRF seems to stimulate vasopressin release.
Raff
H
H
Merrill
D
D
Skelton
M
M
Cowley
A W
AW
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects; D006854:Hydrocortisone / Q000378:metabolism*; D007016:Hypophysectomy; D007022:Hypotension / Q000139:chemically induced / Q000503:physiopathology; D008297:Male; D009599:Nitroprusside / Q000494:pharmacology; D010904:Pituitary Gland, Posterior / Q000502:physiology*; D014667:Vasopressins / Q000378:metabolism*
D014667:Vasopressins; D009599:Nitroprusside; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone