title: Stress-induced salivary cortisol secretion during hypobaric hypoxia challenge and in vivo urinary thromboxane production in healthy male subjects.
abstract: Few studies have assessed the effects of stress on in vivo platelet activation. In the present study, hypobaric hypoxia induced by rapid decompression during high-altitude simulated flight in a hypobaric chamber was used to evaluate the effects of environmental stress on salivary cortisol and urinary thromboxane metabolite (TXM) excretion, a noninvasive marker of in vivo platelet function. Twenty-one male aviators (mean ± SD age = 36 ± 7 years) experiencing hypoxia by removing their oxygen mask for 4-5 min during a simulated flight to 25,000 ft (7,620 m; pO(2) = 59.17 mmHg) and a matched control group of thirteen flying instructors wearing oxygen masks during the challenge, were studied. Hypobaric hypoxia induced a transient significant increase (P < 0.001) in the aviators' salivary cortisol concentration; the overall pattern of diurnal cortisol fluctuation was maintained in both groups. Urinary TXM showed a significant ∼30% reduction (P < 0.01) after the chamber session in aviators exposed to hypobaric hypoxia, but not in controls. A significant inverse correlation was found between salivary cortisol and urinary TXM in aviators (r = - 0.64, P = 0.0015). Salivary cortisol was a significant predictor (P < 0.001) for urinary TXM concentrations in aviators. In conclusion, here we observed that an acute stress-induced salivary cortisol increase was associated with reduced urinary thromboxane biosynthesis, providing the first indirect evidence for an inhibitory effect of acute stress on in vivo platelet function.
authors: Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, Rome, Italy.
authors: Simona
authors: S
authors: Simeoni
authors: Roberto
authors: R
authors: Biselli
authors: Raffaele
authors: R
authors: D'Amelio
authors: Bianca
authors: B
authors: Rocca
authors: Stefano
authors: S
authors: Lattanzio
authors: Luciana
authors: L
authors: Mucci
authors: Giovanni
authors: G
authors: Davì
authors: Francesca Romana
authors: FR
authors: Patacchioli
mesh_terms: D000328:Adult; D000532:Altitude Sickness / Q000503:physiopathology*; D015237:Dinoprost / Q000031:analogs & derivatives / Q000652:urine; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D012463:Saliva / Q000737:chemistry*; D013312:Stress, Physiological / Q000502:physiology*; D013929:Thromboxane B2 / Q000031:analogs & derivatives* / Q000652:urine
chemical_list: C075750:8-epi-prostaglandin F2alpha; D013929:Thromboxane B2; C049235:11-dehydro-thromboxane B2; D015237:Dinoprost; D006854:Hydrocortisone