In the U.S. experts are expounding on the association between salivary analytes and everything from weight gain to the ability to have healthy relationships.
At Salimetrics we are simultaneously buoyed and burdened by this. After 20 years of research involving development and integration of salivary assays into behavioral and health science, we think the field is ready to begin to translate what we have learned so it can benefit the world.
We suspect you concur and we're inviting you to assist us in speeding the research lifecycle by participating in our new initiatives to advance salivary analyte-based research: The Spit Report, Spit Camp, and a network of Centers and Laboratories of Excellence
Cortisol
Cortisol (hydrocortisone, Compound F) is the major glucocorticoid hormone produced in the adrenal cortex. Cortisol is actively involved in the regulation of calcium absorption, blood pressure maintenance, anti-inflammatory function, gluconeogenesis, gastric acid and pepsin secretion, and immune function. (1,2,3) Cortisol production has a circadian rhythm. (4) Levels peak in the early morning and drop to the lowest concentration at night. (5) Levels rise independently of circadian rhythm in response to stress. (6) Increased cortisol production is associated with Cushing’s syndrome and adrenal tumors, while decreased cortisol production is associated with adrenal insufficiency (e.g., Addison’s disease) and adrenocorticotropic hormone (ACTH) deficiency. (7)
In the blood only 1 to 15% of cortisol is in its unbound or biologically active form. The remaining cortisol is bound to serum proteins. (8) Unbound serum cortisol enters the saliva via intracellular mechanisms, and in saliva the majority of cortisol remains unbound to protein. (9)
Salivary cortisol levels are unaffected by salivary flow rate or salivary enzymes. (10) Studies consistently report high correlations between serum and saliva cortisol, indicating that salivary cortisol levels reliably estimate serum cortisol levels. (11,12,13)
References
1. Migeon, C.J., & Lanes, R.L. (1990). Adrenal cortex: hypo- and hyperfunction. In F. Lifshitz (ed.), Pediatric endocrinology, a clinical guide (2nd ed.), (pp. 333-52). New York: Marcel Dekker.
2. Drucker, S., New, M.I. (1987). Disorders of adrenal steroidogenesis. Pediatr Clin North Am, 34(4), 1055-66.
3. Fischbach, F.T. (1992). The manual of laboratory and diagnostic tests, (4th ed.). Philadelphia: J. B. Lippincott.
4. Dorn, L.D., Lucke, J.F., Loucks, T.L., Berga, S.L. (2007). Salivary cortisol reflects serum cortisol: analysis of circadian profiles. Ann Clin Biochem, 44(pt 3), 281-84.
5. Chernow, B., Alexander, H.R., Smallridge, R.C., et al. (1987). Hormonal responses to graded surgical stress. Arch Intern Med, 147(7), 1273-78.
6. Kreiger, D.T. (1975). Rhythms of ACTH and corticosteroid secretion in health and disease and their experimental modification. J Steroid Biochem, 6(5), 758-91.
7. Rothfield, B. (1974). Plasma cortisol. In: B. Rothfield (ed.), Nuclear medicine–in vitro (pp. 120-5). Philadelphia: Lippincott.
8. Robin, P., Predine, J., Milgrom, E. (1977). Assay of unbound cortisol in plasma. J Clin Endocrinol Metab, 46(2), 277-83.
9. Vining, R.F., McGinley, R.A., Symons, R.G. (1983). Hormones in saliva: mode of entry and consequent implications for clinical interpretation. Clin Chem, 29(10), 1752-56.
10. Vining, R.F., McGinley, R.A. (1987). The measurement of hormones in saliva: Possibilities and pitfalls. J Steroid Biochem, 27(1-3), 81-94.
11. Francis, S.J., Walker, R.F., Riad-Fahmy, D., et al. (1987). Assessment of adrenocortical activity in term newborn infants using salivary cortisol determinations. J of Pediatrics, 111, 129-33.
12. Hiramatsu, R. (1981). Direct assay of cortisol in human saliva by solid phase radioimmunoassay and its clinical applications. Clinica Chimica Acta, 117, 239-249.
13. Vining, R.F., McGinley, R.A., Maksvytis, J.J., Ho, K.Y. (1983). Salivary cortisol: A better measure of adrenal cortical function than serum cortisol. Ann Clin Biochem, 20(pt 6), 329-35.
Some important Links to Stress Research:
Link to Prof Douglas Granger Johns Hopkins University: Center Salivary Bioscience
Link to Westminster University Cortisol Research: Link