title: Aspirin inhibits vasopressin-induced hypothalamic-pituitary-adrenal activity in normal humans.
abstract: PGs influence ACTH secretion. However, their specific role in modulating the activity of the human hypothalamic-pituitary-adrenal (HPA) axis remains unclear. Acetylsalicylic acid (aspirin) inhibits the synthesis of PGs from arachidonic acid by blocking the cyclooxygenase pathway. In this study we administered a single, clinically relevant dose of aspirin before HPA axis stimulation by a bolus dose of iv arginine vasopressin (AVP) to seven normal males using a randomized, placebo-controlled, single blinded design. Aspirin significantly reduced the cortisol response to AVP [mean peak increase from basal, 221.1 +/- 20.1 vs. 165.4 +/- 22.5 nmol/L (P = 0.0456); mean integrated response, 11,199.3 +/- 1,560.0 vs. 6,162.3 +/- 1,398.6 nmol.min/L (P = 0.0116) for placebo aspirin/AVP and aspirin/ AVP, respectively]. The ACTH response was reduced, but did not reach statistical significance [mean peak increase from basal, 7.5 +/- 2.2 vs. 4.3 +/- 0.3 pmol/L (P = 0.0563); mean integrated response, 142.6 +/- 36.0 vs. 96.2 +/- 8.7 pmol.min/L (P = 0.12) for placebo aspirin/ AVP and aspirin/AVP, respectively]. PGs may influence ACTH secretion by being stimulatory or inhibitory to the HPA axis at different levels, such as hypothalamic or pituitary. Which effect predominates in vivo during dynamic activation of the axis may depend on the level at which the secretory stimulus acts. We showed that when normal male volunteers were treated with the PG synthesis inhibitor, aspirin, they had a blunted HPA axis response to the pituitary corticotroph stimulator, AVP.
authors.affiliation: Department of Medicine, University of Queensland, Australia.
authors.forename: E J
authors.initials: EJ
authors.lastname: Nye
authors.forename: G I
authors.initials: GI
authors.lastname: Hockings
authors.forename: J E
authors.initials: JE
authors.lastname: Grice
authors.forename: D J
authors.initials: DJ
authors.lastname: Torpy
authors.forename: M M
authors.initials: MM
authors.lastname: Walters
authors.forename: G V
authors.initials: GV
authors.lastname: Crosbie
authors.forename: M
authors.initials: M
authors.lastname: Wagenaar
authors.forename: M
authors.initials: M
authors.lastname: Cooper
authors.forename: R V
authors.initials: RV
authors.lastname: Jackson
mesh_terms: D000293:Adolescent; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D001127:Arginine Vasopressin / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D001241:Aspirin / Q000494:pharmacology*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D006801:Humans; D006854:Hydrocortisone / Q000037:antagonists & inhibitors / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects*; D008297:Male; D010913:Pituitary-Adrenal System / Q000187:drug effects*; D012016:Reference Values; D016037:Single-Blind Method
chemical_list: D016861:Cyclooxygenase Inhibitors; D001127:Arginine Vasopressin; D000324:Adrenocorticotropic Hormone; D001241:Aspirin; D006854:Hydrocortisone