Stress reaction is an essential part of the everyday life, not only in humans but also in animals. By the help of this reaction, we are able to cope with and adapt to the changes occurring in our internal and external environment. These changes are various and theoretically uncountable, including but not limited to different kinds of psychological and metabolic stress types. Moreover, continuous stress is associated with deterioration of the health and the development of diseases. As it is impossible to avoid stress, its management becomes very important. In that regards, it is necessary to assess stress level in various physiological conditions and to determine its role in pathophysiology of disease progression.
Stress is managed by the hypothalamo-pituitary-adrenal axis (HPA) releasing cortisol in humans and corticosterone in rodents. Measurement of cortisol in human saliva is non-invasive method very suitable for stress studies. In order to avoid white coat effect, cortisol measurement in saliva is an excellent method compared to invasive blood withdrawal. More importantly, salivary cortisol is free or the active form of cortisol whereas blood cortisol reflects both free and bound cortisol. Therefore in the last decades salivary cortisol measurement has become a powerful tool for psychoneuroendocrinological studies. Moreover, free cortisol is also accumulated in hair and thus, its measurement in hair provides retrospective cortisol levels. This approach might be very useful in studying the role of stress in disease progression.
In rodents, the final product of this axis is corticosterone. Thus measurement of cortisol and corticosterone are main objective parameters in stress studies. Y immunotek has developed specific ELISA tests for the measurement and quantification of both hormones in saliva, in blood plasma and serum, in hair samples, and in urine. Moreover, fecal measurement cortisol or corticosterone may also be possible for assessment of stress in wild animals.
Below are the examples to the studies that investigated salivary cortisol in humans or corticosterone in rodents:
The hypothalamic-pituitary-adrenal axis activity in archers: cortisol release, stress, anxiety and success. Kayacan Y, Derebasi DG, Ucar C, Ozgocer T, Yildiz S.J Sports Med Phys Fitness. 2022 Jan;62(1):139-148. doi: 10.23736/S0022-4707.21.11811-0. Epub 2021 Jun 1.PMID: 34080811
Maternal viral mimetic administration at the beginning of fetal hypothalamic nuclei development accelerates puberty in female rat offspring. Cakan P, Yildiz S, Ozgocer T, Yildiz A, Vardi N.Can J Physiol Pharmacol. 2018 May;96(5):506-514. doi: 10.1139/cjpp-2016-0535. Epub 2017 Aug 21.PMID: 28825971
Effects of late-night eating of easily-or slowly-digestible meals on sleep, hypothalamo-pituitary-adrenal axis, and autonomic nervous system in healthy young males. Uçar C, Özgöçer T, Yıldız S.Stress Health. 2021 Oct;37(4):640-649. doi: 10.1002/smi.3025. Epub 2021 Jan 19.PMID: 33426778 Clinical Trial.
Cortisol Awakening Response and Heart Rate Variability in the Menstrual Cycle of Sportswomen. Kayacan Y, Makaracı Y, Ozgocer T, Ucar C, Yıldız S.Res Q Exerc Sport. 2021 Dec;92(4):760-769. doi: 10.1080/02701367.2020.1774486. Epub 2020 Aug 27.PMID: 32853053
Does Psychodrama Affect Perceived Stress, Anxiety-Depression Scores and Saliva Cortisol in Patients with Depression? Erbay LG, Reyhani İ, Ünal S, Özcan C, Özgöçer T, Uçar C, Yıldız S.Psychiatry Investig. 2018 Oct;15(10):970-975. doi: 10.30773/pi.2018.08.11.2. Epub 2018 Oct 11.PMID: 30301307 Free PMC article.
Cortisol awakening response is blunted and pain perception is increased during menses in cyclic women. Ozgocer T, Ucar C, Yildiz S.Psychoneuroendocrinology. 2017 Mar;77:158-164. doi: 10.1016/j.psyneuen.2016.12.011. Epub 2016 Dec 21.PMID: 28064085
Stress in couples undergoing assisted reproductive technology. Tuncay G, Yıldız S, Karaer A, Reyhani I, Özgöcer T, Ucar C, Karabulut U, Unal S.Arch Gynecol Obstet. 2020 Jun;301(6):1561-1567. doi: 10.1007/s00404-020-05549-8. Epub 2020 Apr 28.PMID: 32347354
Long-term metabolic cage housing increases anxiety/depression-related behaviours in adult male rats. Sahin Z, Solak H, Koc A, Ozen Koca R, Ozkurkculer A, Cakan P, Solak Gormus ZI, Kutlu S, Kelestimur H.Arch Physiol Biochem. 2019 May;125(2):122-127. doi: 10.1080/13813455.2018.1441314. Epub 2018 Feb 20.
Daily cortisol awakening response and menstrual symptoms in young females. Ozgocer T, Ucar C, Yildiz S.Stress Health. 2022 Feb;38(1):57-68. doi: 10.1002/smi.3074. Epub 2021 Jun 24.PMID: 34137165
The effect of stress-induced cortisol increase on the sense of ankle proprioception.Şenol D, Uçar C, Çay M, Özbağ D, Canbolat M, Yıldız S.Turk J Phys Med Rehabil. 2018 Aug 15;65(2):124-131. doi: 10.5606/tftrd.2019.2457. eCollection 2019 Jun.PMID: 31453552 Free PMC article.
Is amygdala size correlated with stress? Canbolat M, Erbay MF, Şenol D, Uçar C, Yıldız S.Folia Morphol (Warsz). 2021;80(3):514-519. doi: 10.5603/FM.a2020.0095. Epub 2020 Aug 22.PMID: 32827309 Free article.
Anxiety and Salivary Cortisol Levels in Children Undergoing Esophago-Gastro-Duodenoscopy Under Sedation. Kara D, Bayrak NA, Volkan B, Uçar C, Cevizci MN, Yildiz S.J Pediatr Gastroenterol Nutr. 2019 Jan;68(1):3-6. doi: 10.1097/MPG.0000000000002142.PMID: 30169453
Preparatory information reduces gastroscopy-related stress in children as confirmed by salivary cortisol. Volkan B, Bayrak NA, Ucar C, Kara D, Yıldız S.Saudi J Gastroenterol. 2019 Jul-Aug;25(4):262-267. doi: 10.4103/sjg.SJG_493_18.PMID: 31044746 Free PMC article. Clinical Trial.
Effect of increase in cortisol level due to stress in healthy young individuals on dynamic and static balance scores. Cay M, Ucar C, Senol D, Cevirgen F, Ozbag D, Altay Z, Yildiz S.North Clin Istanb. 2018 May 29;5(4):295-301. doi: 10.14744/nci.2017.42103. eCollection 2018.PMID: 30859159 Free PMC article.
Cesarean delivery is associated with suppressed activities of the stress axes. Uçar C, Bülbül M, Yıldız S.Stress. 2022 Jan;25(1):67-73. doi: 10.1080/10253890.2021.2015318. Epub 2021 Dec 21.PMID: 34931594
Analysis of the effects of hypothalamic-pituitary-adrenal axis activity in menstrual cycle on ankle proprioception, dynamic balance scores and visual-auditory reaction times in healthy young women. Şenol D, Uçar C, Toy Ş, Kısaoğlu A, Özbağ D, Ersoy Y, Yıldız S.J Musculoskelet Neuronal Interact. 2021 Mar 1;21(1):85-92.PMID: 33657758 Free PMC article.
Late-night exercise affects the autonomic nervous system activity but not the hypothalamo-pituitary-adrenal axis in the next morning. Uçar C, Özgöçer T, Yildiz S.J Sports Med Phys Fitness. 2018 Jan-Feb;58(1-2):57-65. doi: 10.23736/S0022-4707.16.06766-9. Epub 2016 Nov 16.PMID: 27849113
