Advantages and Reliability of Saliva Testing
and Clinical Applications

Advantages and Reliability of Saliva Testing

The tests employ saliva samples that are collected at the patient's convenience. Patient samples are mailed to the laboratory without involving clinic staff and with no biohazard risks; no blood, no mess. The test also avoids the inconvenience of a woman collecting urine samples over a 24 hour time span.

Economical. The 6 hormone saliva profile costs less than either serum testing for Estradiol and Progesterone on a random blood sample or a steroid hormone profile on a 24 hour urine specimen.

Scientific Advantages. Correlation with Free Bioactive Fraction in Blood: The general consensus is that target cells (cells that have specific hormone receptors on their outer membranes) are most influenced by the free fractions (not bound to plasma proteins) of the steroids. The bioactive or the free fractions of the steroidal hormones are able to filter into the interstitial space and easily gain entry into their target cells.

Saliva is a Valuable Diagnostic Tool for Hormone Assessment

Article by Michel Y. Farhat, Ph.D and Elias F. Ilyia, Ph.D

The use of saliva as a vehicle for determination of plasma steroid hormone levels has increased dramatically in recent years. Since 1983, more than 2500 papers and research articles dealing with salivary diagnostic tests have been published1. Both clinicians and investigators have used saliva to assess numerous clinical problems including, digitalis toxicity, celiac disease, liver function and immunodeficiency. Saliva has also been used for pharmakicokinetic studies and therapeutic drug monitoring in a variety of clinical situations. The value of saliva as a monitoring medium resides in the fact that it is easy to collect, store and ship, and is non-invasive, thus convenient for multiple sampling.

Plasma-saliva transfer. The reliability of saliva testing depends on establishing a direct correlation between saliva and plasma concentration of a particular substance. The transfer of substances from plasma into the saliva is dependent on their physiochemical properties1. A small molecular weight and a great lipid solubility are normally associated with a faster transfer rate. A good correlation has also been established between saliva/plasma ratio of substances, their pKa and salivary pH. Salivary flow rate and the existing pathophysiology of the oral cavity have also been shown to affect salivary distribution of substances

Saliva concentration of a particular hormone is dependent on the affinity and total binding capacity of various binding proteins in plasma. As blood passes through salivary glands, free "unbound" and weakly bound (low affinity binding protein) forms of hormones will diffuse through the salivary gland epithelium into the saliva. As in other clearing organs, membrane transfer occurs in both directions, is passive for most substances and equilibrium is governed by the transmembrane concentration gradient. Thus, saliva levels reflect the free concentration of hormones in plasma, and in the absence of high affinity, high capacity-binding proteins, these levels correlate with plasma concentrations. On the other hand, hormones that have high affinity, high capacity-binding proteins, such as thyroxine, are difficult to assay in the saliva. These hormones have a very high plasma total to free hormone ratio and exist in small amounts in saliva.

Salivary steroid hormone analysis. Monitoring plasma steroid levels is essential for the clinical assessment of a patient's endocrine function. Saliva becomes an important diagnostic tool, since in many instances, the standard plasma and urine sampling techniques may not provide the optimum sampling conditions. Some of the problems that diagnostic laboratories had to overcome in establishing the validity of salivary steroid assays, were to determine whether steroid concentration in saliva can be measured with accuracy and whether these small values are meaningful and correlate with plasma levels or any other physiological parameter. ,Salivary steroid levels tend to be much lower than those in plasma, because they reflect the level of unbound steroid, which represents about 2-5% of total plasma concentration. Salivary glands may also transform certain steroids during their passage across the salivary epithelium3. Highly polar molecules, such as sugars and conjugated steroids do not cross the lipid lining of cells and can only get into whole saliva via blood contamination from small cuts and ulcers or from gingival fluid. Here we review the pharmacodynamics and partitioning of few hormones, that have been characterized in saliva and evaluate the correlations between their saliva and plasma concentrations. Progesterone Progesterone was one of the first steroids to be reliably assayed in human saliva. Once saliva samples are collected, salivary progesterone concentrations remain stable under a wide range of handling conditions. Because of its high circulating blood levels (ng/ml during luteal phase), saliva concentrations of the hormone usually remain within the limits of sensitivity of most conventional assays. Average salivary progesterone concentrations vary from 20-100 pg/ml during the follicular phase to 100-500 pg/ml during the luteal phase (Figure 1). Progesterone levels are also affected by women's age, degree of activity, nutrition and race4,5. A high correlation coefficient (between 0.8 and 1.0) has been established between plasma and salivary levels of the hormone6,7, making saliva a useful diagnostic tool. Serial measurement of salivary progesterone has been used to assess ovarian function, and in particular for diagnosis of defective or inadequate luteal function, as well as to monitor response to hormone therapy. Other clinical applications may include monitoring placental function by repetitive measurement of salivary progesterone during pregnancy9.

Estradiol Salivary estradiol (E2) is about 1-2% of total plasma values, Earlier studies, using assays with variable sensitivities and specificities, have described a wide range of salivary estradiol levels. Three independent studies using radioimmunoassay10-12, enzyme immunoassay13 and chemi-luminescence immunoassay14 have reported comparable salivary E2 levels during normal nonstimulated menstrual cycles ranging from 5-15, 10-30 and 7-20 pmol/L during the follicular, periovulatory and luteal phase, respectively (Figure 2). These levels in stimulated cycles ranged from 10 to 120 pmol/L15. Moreover, Wong et al.10 showed a mid-cycle salivary E2 peak, corresponding to the mid-cycle LH surge, followed by a midluteal rise. In these women, the changes in salivary E2 were similar to the E2 pattern in serum, with a high degree of correlation (r=0.93). A similar correlation (r=0.96) was observed between salivary E2 + estrone and free plasma E2 in FSH-stimulated cycles13. Testosterone Under physiological conditions, a very good correlation exists between salivary and serum testosterone (T) in men16,17. Wang et al. have demonstrated that following exogenous T Salivary cortisol exhibits clear diurnal variation and circadian rythmicity both in normal and depressed individuals. Salivary cortisol is highest in the morning and varies between 13 and 23 nmoles/L These levels decrease significantly during the day and reach their lowest value at night (1-3 nmoles/L) (Figure 3).

Dehydroepiandrostenedione (DHEA) DHEA ia an adrenal steroid produced in abundant amounts and is conjugated to sulfate to form DHEAS before its release into the circulation32. DHEA and DHEAS are interconvertable and exist in dynamic equilibrium with each other33. Salivary DHEAS is found in saliva at about 0.1% of its plasma concentration. Serum fluctuations in DHEA(S) concentrations are accurately and rapidly reflected in salivary levels.34Other hormones Salivary estriol levels are also high, easy to measure and correlate well with plasma unbound unconjugated estriol35,36. Androstenedione can also be measured with sufficient accuracy in saliva. The absence of specific high affinity binding proteins for androstenedione, results in a linear relationship between plasma total and plasma free fraction, and hence an excellent correlation between plasma and saliva levels of the hormone37.

Conclusion. The above studies clearly demonstrate that saliva is a useful diagnostic tool for measurement of steroid hormones. Salivary concentration represents the free form of a particular hormone, and thus is a true reflection of its bioactivity. Moreover, the non-invasive nature of saliva collection and the convenience of multiple sample facilitate the design of functional assays for the assessment of various endocrine functions. In a recent review, Mandel38 has likened saliva to a mirror reflecting the emotional, hormonal, immunological as well as nutritional and metabolic status of the body. The broad spectrum of interactions and relationships among these factors opens a whole field of diagnostic possibilities worth exploring and evaluating.

References

1. Malamud D. Br Med J. 305: 207-208, 1992.
2. Mandel ID. J Oral Pathol 19: 119-125, 1990.
3. Ferguson DB. Ed. Front Oral Physiol. Karger, Basel: 5: 1-162, 1984.
4. Lipson SF and Ellison PT. Am J Human Biol 1:249-255, 1989.
5. Frisch RE. Hum Reprod 2: 521-533, 1987.
6. Meulenberg PM and Hoffman JA. Clin Chem 35:168-172, 1989.
7. Vuorento T, Lahti A, Hovatta O and Huhtaniemi I. Scand J Clin Lab Invest xxxxx xx49:395-401, 1989.
8. Walker SM, Walker RF and Riad-Fahmy D.Horm Res 20: 231-240, 1984.
9. Connor ML, Sanford LM and Howland BE. Can J Physiol Pharmacol 60: 410-413, 1982.
10. Wong YF, Mao K, Panesar N, Loong EPL, Chang AMZ and Mi ZJ. Eur J Obstet xxxGynecol Reprod Biol 34: 129-135, 1990.
11. Evans JJ, Steward CR, Merrick AY. Br J Obstet Gynaecol 87:624-626, 1980.
12. Berthonneau J, Tanguy G, Janssens Y, et al. Human Reprod 4: 625-628, 1989.
13. Mounib N, Sultan CH, Bringer J, Hedon B, Nicolas JC, Cristol P, Bressot N and xxxDescomps. J Steroid Biochem 31:861-865, 1988.
14. Deboever J, Kohen F, Bouve J, Leyseele D and Vanderkerckhove D. Clin Chem xxx36: 2036-2041, 1990.
15. Smith RG, Besch PK, Dill B, Buttram Jr VC. Fertil Steril 31: 513,1979.
16. Walker RF, Wilson DW, Read GF, Riad-Fahmy D. Int J Androl 3: 105,1980.
17. Gaskell SJ, Pike AW, and Griffiths K. Steroids 36: 219-228, 1980.
18. Baxendale PM and James VHT. In: Immunoassays for Clinical Chemistry. Hunter WM and Corrie JET, eds. Churchill Livingstone, New York. pp. 430-444, 1983.
19. Gould VG, Turkes AO and Gaskell SJ. J Steroid Biochem 24:563-567, 1986.
20. Read GF, Harper ME, Peeling WB and Griffiths K. Int J Androl 4: 623-627, 1981.
21. Cook NJ, Read GF, Walker RF, Harris B and Riad-Fahmy D. Eur J Appl Physiol 55: xxx634-638. 1986.
22. Vining RF, McGinley RA, Maksvytis JJ and Ho KY. Ann Clin Biochem 20: 329-335, xxx1983.
23. Laudat MH, Cerdas S, Fournier C, Giuban D et al. J Clin Endocrinol Metab 66: 343-348, xxx1988.
24. Vining RF, McGinley RA and Symons RG. Clin Chem 29: 1752:1756, 1983.
25. Umeda T, Hiramatsu R, Iwaoka T, Shimada T, Miura F and Sato T. Clin Chem Acta 110: xxx245-253, 1981.
26. Peters JR, Walker RF, Riad-Fahmy D and Hall R. Clin Endocrinol 17: 583-592, 1982.
27. Kahn JP, Rubinow DR, Davis CL, Kling M and Post RM. Biol Psychiatry 23: 335-349, xxx1988.
28. Tunn S, Mollmann H, Barth J, Derendorf H and Krieg M. Clin Chem 38: 1491-1494, 1992.
29. Cook NJ, Read GF, Walker RF, Harris B and Riad-Fahmy D. Eur J Appl Physiol 55: xxx634-638, 1986.
30. O'Connor P and Corrigan DL. Med Sci Sports Exdrcise 19: 224-228, 1987.
31. Tarui H and Nakamura A. Aviat Space Environ Med 58:573-575, 1987. 32. Guechot J et al. Neuropsychobiology 18: 1-4, 1987. 33. Ratcliffe JG. In: Adrenal Cortex, Eds. Anderson DC, Winter JD. pp. 188-205, 1985. 34. Walker R et al. 9th Tenovus Workshop, Cardiff, UK, 1982. 35. Robinson J, Walker S, Read GF and Riad-Fahmy D. Lancet i: 1111-1112, 1981. 36. Fischer-Rasmussen W, Gabrielsen MV and Wisborg T. Acta Obstet Gynecol 60: 417-420, xxx1982. 37. Turkes AO and Read GF. In: Immunoassays of steroids in saliva. Read GF, Riad-Fahmy D, xxxand Walker RF and Griffiths K, eds. pp. 228-238, 1984 Alpha Omega, Cardiff. 38. Mandel ID. Ann NY Acad Sci 694: 1-10, 1993.

Abstracts of additional studies:

Salivary progesterone: Relation to total and non-protein bound blood levels. J. Steroid Biochem. Vol. 23, No. 6A, pp. 975-979, 1985

The daily amounts of salivary progesterone have been determined over the complete menstrual cycle for 9 normal women. The level of progesterone during the follicular phase was about 150 pmol/l and increased significantly to about 350 pmol/l during the luteal phase of the menstrual cycle. The amounts of salivary progesterone were significantly correlated with those in blood (P<0.001) in paired saliva-blood specimens taken from 96 women. Although these volunteers comprised patients with benign and malignant breast disease and normal unaffected women, the relationship between salivary and blood progesterone was similar for all groups. The concentration of non-protein bound progesterone was determined using equilibrium dialysis. To correct for serum dilution, the linear relationship between the percentage of progesterone bound and the reciprocal of serum dilution has been exploited. The values of non-protein bound progesterone obtained were significantly and linearly correlated with levels in saliva (r=0.75, P<0.001, d.f.=34) although the amount of free progesterone in blood was about five times that found in saliva.

Salivary testosterone measurements: Reliability across hours, days and weeks. Dabbs, J.M., Jr. Salivary Testosterone Measurements: Physiology & Behavior, Vol. 48, pp. 83-86. © Pergamon Press 1990

Salivary testosterone measurements would appear to be useful in behavioral research, where subjects are often reluctant to provide serum samples. The usefulness of salivary measurements depends upon their reliability, however, which was the focus of the present investigation. In four studies, 270 male and 175 female subjects collected saliva samples at times ranging from 30 min. to 8 weeks apart. Subjects collected samples on at least two days, at time of awakening, midmorning, late afternoon, and late evening. Mean testosterone concentration dropped about 50% from morning to evening for both sexes, with the largest drops early in the day. Mean reliability was r=.64 across two days and r=.52 across 7-8 weeks. Menstrual cycle effects were negligible. Reliability can be increased by using more than one measurement, and it is probably desirable to combine measurements taken several weeks apart. Salivary assays offers a practical way of measuring testosterone in free-ranging subjects outside the laboratory.

Salivary estradiol & progesterone during the normal ovulatory menstrual cycle in Chinese women. Y.F. Wong (1), K. Mao (1), N.S. Panesar (2), E.P.L. Loong (1), A.M.Z. Chang (1) and ZJ. Mi (3) (1) Department of Obstetrics and Gynecology and (2) Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shain, Hong Kong, and Shanghai Institute of Endocrinology, Shanghai, Peoples Republic of China.

Summary: Salivary and serum levels of estradiol and progesterone were measured by radioimmunoassay in 10 Chinese women during their normal menstrual cycles. Changes in salivary estradiol and progesterone levels followed a similar pattern to that in the serum. Significant correlation was found between salivary and serum levels of estradiol and progesterone (p>0.001). Measurements of these salivary steroids may be used to assess follicular dynamics. Moreover, salivary sampling is simple, convenient and stress free. (Figure 1-to be added)

Salivary oestradiol and progesterone levels in premenopausal women with breast cancer D.Y. Wang, et al Eur. J. Cancer Clin. Oncol. 1986; 22: 427

The concentrations of oestradiol and progesterone have been measured in salivary specimens collected daily over a complete menstrual cycle in 12 patients with operable breast cancer and 12 normal control volunteers. There was no significant difference (P>0.005) for either hormone between these two groups. Both showed a mid-cycle rise in oestradiol levels followed by a smaller but sustained increase during the luteal phase. the progesterone concentration increased markedly during the luteal phase of the cycle. Total or non-protein bound oestradiol levels measured in blood samples from 19 normal women were both linearly correlated (P<0.001) with the concentration of oestradiol in matched saliva samples. The amount of free oestradiol in blood was about twice that found in saliva.

Daily measurements of salivary progesterone reveal a high rate of anovulation in healthy students. Scand J Clin Lab Invest 1989; 49: 395-401. D.Y. Wang, et alEur. J. Cancer Clin. Oncol. 1986; 22: 427

Daily concentrations of salivary progesterone (P) were measured from 32 women during a complete menstrual cycle. Seventeen of the subjects were university students and 15 were patients of an infertility clinic (a severe male factor was verified as the cause of infertility in all of them). Commercially available reagents for radio immunoassay of serum P were modified for salivary measurements, to yield acceptable precision and sensitivity (40 pmol/l). Good correlation (r=0.93) was found between salivary and serum P concentrations in samples collected simultaneously. The follicular phase levels of salivary P were below 100 pmol/l, and those at the luteal peak were 390+/-45 poml/l (mean +/- SEM, n=24). From the menstrual salivary P concentration curves we identified the first day of significant elevation above mean follicular levels (T2) and thereafter calculated the cumulative sum of daily P concentrations until 95% of the luteal phase secretion had accumulated (C95). The time needed to reach C95(designated T95) and logC95 were plotted in coordinates and used as the basis of evaluation of normal menstrual P secretion. The observations were distributed in two groups, one with clearly identifiable T2 and distinct luteal-phase P (ovulation had occurred) and one with no identifiable T2 and absent luteal Phase P peak (indicative of anovulation). Interestingly, 47% of the student population had an abnormally low menstrual P profile while all the other subjects displayed a clear luteal-phase peak of salivary P. These data provide more evidence for applicability of salivary P measurements for diagnosis of corpus luteum function and highlights the difficulty of selecting representative reference populations in studies on female reproductive endocrinology.

Characterization of profiles of salivary progesterone concentrations during the luteal phase of fertile and subfertile women. R.F. Walker, D.W. Wilson, P.L. Truran, G.F. Read, G. Richards, S.M. Walder, and D. Riad-Fahmy

Salivary progesterone concentrations were measured in daily samples collected between 08.00 and 09.00 h throughout the menstrual cycle of women with a history of fertility. The luteal-phase salivary progesterone profiles in these normally menstruating, healthy women were characterized using a computer program based on a cumulative sum procedure. This method of statistical analysis led to the development of a 'progesterone boundary diagram', the inner and outer domains of which distinguished between the profiles of salivary progesterone considered compatible with fertility, and those observed in subfertile women attending an infertility clinic.

Follicular growth and corpus luteum function in women with unexplained infertility, monitored by ultrasonography and measurement of daily salivary progesterone. M.M. Finn*, J.P. Gosling, D.F. Tallon*, L.A. Joyce, F.P. Meehan*, and P.F. Fottrell Gynecol. Endocrinol. 3 (1989) 2979-308

Ovarian function was evaluated over a minimum of 3 consecutive menstrual cycles from each of 41 women with unexplained infertility. Follicular development and ovulation were monitored using real time ultrasonography and luteal function was evaluated by daily salivary progesterone measurement. In 129 spontaneous cycles, normal single ovulations were detected in 121 (93.8%). Luteal phase insufficiency was identified in 21 (17.4%) of these 121 cycles and this was a recurrent phenomenon in the cycles of 5 of the 41 women (12.2%). A successful pregnancy was seen only in association with consistently normal salivary progesterone profiles or share the empirical use of clomiphene citrate therapy had corrected previously diagnosed luteal phase insufficiency. Basal body temperature records or mid-luteal serum progesterone measurements were less satisfactory indices of luteal function than salivary progesterone profile.

Topical Progesterone cream application and overdosing. Elias Ilyia Ph.D., Deborah McLure B.S., and Micheal Farhat Ph.D., J. Altern. Compl. Med. 4:1, 1998.

Case Report 1: A 52 year old perimenopause woman was prescribed cyclical progesterone augmentation to alleviate her post menopause like symptoms. She had been on 1/8 of a teaspoon of transdermal 5% progesterone cream twice a day (between days 4 and 20 of her 24 day menstrual cycle) when she was referred to our laboratory for assessment of her female hormone profile. Ten saliva samples were collected at day 2 of the cycle and every 2-3 days thereafter, and salivary Estradiol and Progesterone levels were determined by an E.L.I.S.A. assay (1). The patient hormone profile shows significantly elevated progesterone (P1 levels>1,000 pg/ml) between days 5 and 25 (normal salivary P1 range <500 pg/ml). P1 levels remained abnormally high even when the progesterone cream was not being used as seen on day 2, reflecting carryover from the previous cycle and day 24 showing carryover in the present cycle. (Figure 2- to be added)

Case Report 2: A 36 year old female had been receiving hormone replacement therapy since she had undergone total hysterectomy a few years earlier. Her treatment consisted of an estrogen patch (Estraderm, 0.1%) per day and 1/4 of a teaspoon of 5% progesterone cream, twice a day. As in the previous case, her hormone profile revealed significantly exaggerated salivary progesterone levels (>1,000 pg/ml) throughout the collection. (Figure 2- to be added) Discussion: Progesterone augmentation is prescribed to women to alleviate various somatic and emotional symptoms associated with hormonal imbalance or menopause. The transdermal delivery of hormones is generally more acceptable to women since it provides some advantages over the oral routes of administration. By bypassing the liver, transdermal delivery allows for use of lower doses of steroids for a long-lasting action and avoids some of the potential drawbacks associated with hepatic steroid metabolism. (2) The pharmacokinetics of transdermal steroid delivery, however, are not well-defined. The two cases illustrated in this report clearly demonstrate that progesterone creams even when administered in small doses caused abnormally elevated circulation free fraction levels of the hormone. Moreover, sequential measurements show that the hormone levels remain significantly elevated up to 60 days even after discontinuation of the cream. In our hands, we find that approximately 90-95% of all specimens referred to our laboratory from women using topical P1 creams, show significant salivary hormone elevation. Salivary progesterone is an accurate reflection of the free circulating plasma levels of the hormone (3). The most common set of complaints reported to our laboratory by these women include gradual water retention and gradual increase in body weight as well as breast engourgement and a mild to moderate depression that becomes clinically evident in the 6th to 9th month of dermal P1 use.

In conclusion, these studies suggest that women using transdermal creams should be closely monitored for overdosage, and that perhaps the use of alternative modes of progesterone administration should be considered, until more data characterizing the pharmacokinetics of progesterone creams are available.

Long-Term Effects of Topical Progesterone Cream Application: A Case Study Article by Elias F. Ilyia, Ph.D., Deborah McLure, B.Sc., and Michel Y. Farhat, Ph.D

It has been observed that the premenstrual tension, bloating as well as mood swings and depression, experienced by perimenopausal women can be relieved by exogenous progesterone administration, as part of a well-balanced hormone replacement regimen. Natural progesterone is derived from plants, is isomolecular to human progesterone and is available to women in over-the-counter gels and creams. The pharmacodynamics of transdermal creams are unknown, and thus self-medication may lead to overuse and overdose as well as exacerbation of the symptoms. We describe the case of a forty five year-old woman showing excessive elevations in salivary progesterone, following use of low pharmacological concentrations of progesterone cream. The elevated progesterone levels were maintained for months after cessation of cream use. Salivary testing, a measure of the free fraction of the hormone, is used to assess the patient hormonal profile. This report illustrates the problem of overdosing with topical application of progesterone creams and the long-term side effects associated with it. Discussion Self-medication with over-the-counter progesterone (as well as estrogen) creams is widespread among women to relieve premenstrual-like symptoms, and in some cases as a form of hormone replacement therapy. Transdermal delivery of hormonal steroids offers a number of advantages over other modes of administration. Transdermal delivery normally allows the use of small amounts of the hormone for a long-lasting effect by avoiding chemical or metabolic degradation of drugs that may occur in the gut. The high efficiency of this system may also result from the ability to modify the properties of the stratum corneum to absorption by using iontophoretic devices and flux enhancers (3). Moreover, by bypassing the liver, transdermal delivery eliminates the potential drawbacks associated with hepatic steroid metabolism (4). However, the absence of wide-range controlled studies to monitor the pharmacokinetics and biological effects of transdermal progesterone application in the general population makes the efficacy of this mode of treatment, at least with regard to certain applications, questionable. xxSteroid hormones in plasma are either free or bound to specific and non-specific binding proteins. More than 95 per cent of steroids in plasma are bound, leaving target tissues exposed to less than 5 per cent of the total plasma concentration which constitutes the free fraction of the hormone (5). The free concentration of a hormone depends on the affinity and total binding capacity of various binding proteins in plasma. The entry of steroid hormones in saliva occurs primarily by passive diffusion, and is driven by the plasma concentration gradient of its free fraction. Thus, saliva levels will reflect the free concentration of hormones in plasma. In the absence of both a high affinity, high capacity binding protein in the plasma, the concentration of a particular hormone in saliva will correlate with its total plasma concentration. Wong et al. (1), monitoring ovarian function in a group of Chinese women, found very similar salivary and serum estradiol and progesterone profiles during the menstrual cycle. Moreover, Bolaji et al. (6) have shown that in patients using oral micronized progesterone, saliva and serum levels peaked simultaneously and a high degree of correlation (r=0.89) existed between saliva and plasma progesterone concentrations measured concurrently. A similar correlation was also observed between saliva and plasma concentration of other steroids, such as cortisol (7,8). These observations suggest that the free progesterone concentration in saliva closely reflect that in plasma, and thus provide credence to the role of saliva as a diagnostic tool for assessment of hormone levels.

References

1. Wong YF, Mao K, Panesar NS, Loong EPL, Chang AMZ, Mi ZJ. Salivary estradiol and xxxxprogesterone during the normal ovulatory menstrual cycle in chinese women. Eur J Obstet Gynecol xxxReprod Biol 1990; 34:129-135.

2. Vuorento T, Lahti A, Hovatta O, Huhtaniemi I. Daily measurements of salivary progesterone reveal a high xxxxrate of anovulation in healthy students. Scand J Clin Lab Invest 1989; 49:395-401.

3. Berner B, John VA. Pharmacokinetic characterization of transdermal delivery systems. Clin Pharmacokinet xxxx1994; 26: 121-134.

4. Donaldson AS, Jeffcoate L, Sufi SB. Assays of oestradiol and progesterone in saliva in the assessment of xxxxovarian function. Front Oral Physiol 1984; 5:80-86.

5. Quissell DO. Steroid hormone analysis in human saliva. Ann NY Acad Sci USA 1993; 264:143-145.

6. Bolaji II, Tallon DF, O'Dwyer E, Fottrell PF. Assessment of bioavailability of oral micronized xxxxprogesterone using a salivary progesterone enzymeimmunoassay. Gynecol Endocrinol 1993; 7: 101-110.

7. Kahn JP, Rubinow DR, Davis CL, Kling M. Post RM. Salivary cortisol: A practical method for evaluation xxxxof adrenal function. Biol Physchiatry 1988; 23: 335-349.

8. Vining RF, McGinley RA. The measurement of hormones in saliva. J Steroid Boichem 1987; 27: 81-94. 9.xxScheuplein RJ. Percutaneous absorption: Theoretical aspects. In: Mauvais-Jarvis P, Vickers CFH, xxxxWepierre J, Eds. Percutaneous Absorption of steroids. London: Academic Press, 1980: 1-17.