The phosphodiesterases type 5 inhibitor tadalafil reduces the activation of the hypothalamus-pituitary-adrenal axis in men during cycle ergometric exercise.
Phosphodiesterase type 5 inhibitors may influence human physiology, health, and performance by also modulating endocrine pathways. We evaluated the effects of a 2-day tadalafil administration on adenohypophyseal and adrenal hormone adaptation to exercise in humans. Fourteen healthy males were included in a double-blind crossover trial. Each volunteer randomly received two tablets of placebo or tadalafil (20 mg/day with a 36-h interval) before a maximal exercise was performed. After a 2-wk washout, the volunteers were crossed over. Blood samples were collected at -30 and -15 min and immediately before exercise, immediately after, and during recovery (+15, +30, +60, and +90 min) for adrenocorticotropin (ACTH), β-endorphin, growth hormone (GH), prolactin, cortisol (C), corticosterone, dehydroepiandrosterone-sulfate (DHEAS), and cortisol binding globulin (CBG) assays. C-to-CBG (free cortisol index, FCI) and DHEAS-to-C ratios were calculated. Exercise intensity, perceived exertion rate, O₂ consumption, and CO₂ and blood lactate concentration were evaluated. ACTH, GH, C, corticosterone, and CBG absolute concentrations and/or areas under the curve (AUC) increased after exercise after both placebo and tadalafil. Exercise increased DHEAS only after placebo. Compared with placebo, tadalafil administration reduced the ACTH, C, corticosterone, and FCI responses to exercise and was associated with higher β-endorphin AUC and DHEAS-to-C ratio during recovery, without influencing cardiorespiratory and performance parameters. Tadalafil reduced the activation of the hypothalamus-pituitary-adrenal axis during exercise by probably influencing the brain's nitric oxide- and cGMP-mediated pathways. Further studies are necessary to confirm our results and to identify the involved mechanisms, possible health risks, and potential clinical uses.
Unit of Endocrinology, Dept. of Health Sciences, Univ. of Rome "Foro Italico," Rome, Italy. luigi.diluigi@uniroma4.it
Luigi
L
Di Luigi
Paolo
P
Sgrò
Carlo
C
Baldari
Maria Chiara
MC
Gallotta
Gian Pietro
GP
Emerenziani
Clara
C
Crescioli
Serena
S
Bianchini
Francesco
F
Romanelli
Andrea
A
Lenzi
Laura
L
Guidetti
D000305:Adrenal Cortex Hormones / Q000097:blood; D000328:Adult; D054874:Athletic Performance; D001642:Bicycling; D002243:Carbolines / Q000494:pharmacology*; D002352:Carrier Proteins / Q000097:blood; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006801:Humans; D007028:Hypothalamic Hormones / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects*; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects; D058986:Phosphodiesterase 5 Inhibitors / Q000494:pharmacology*; D005082:Physical Exertion; D010907:Pituitary Hormones / Q000097:blood; D010913:Pituitary-Adrenal System / Q000187:drug effects*; D013312:Stress, Physiological / Q000187:drug effects*; D000068581:Tadalafil; D055815:Young Adult
D000305:Adrenal Cortex Hormones; D002243:Carbolines; D002352:Carrier Proteins; D007028:Hypothalamic Hormones; D058986:Phosphodiesterase 5 Inhibitors; D010907:Pituitary Hormones; C027091:cortisol binding globulin; D019344:Lactic Acid; D000068581:Tadalafil