Evaluation of hypothalamo-pituitary-adrenal activity in the tree shrew (Tupaia belangeri) via salivary cortisol measurement

Saliva sampling is frequently used in humans for adrenal glucocorticoid hormone analysis because of advantages such as non-invasiveness, the ease of collection, and storing of the samples. To transfer this advantageous method to laboratory mammals, potentially confounding factors such as stressful handling procedures have to be excluded. In the present study we established a method for collecting saliva for cortisol measurement in freely moving adult male tree shrews (Tupaia belangeri). The practicability of the procedure was demonstrated (i) by stress-induced changes in cortisol levels revealing a significant increase during the stress phase (control = 0.91 nmol/l vs stress = 1.71 nmol/l), and (ii) by reporting no significant differences in salivary cortisol levels before and after performance of a learning task. The present study emphasizes the use of salivary cortisol analysis especially for monitoring acute changes in the hypothalamo-pituitary-adrenal axis activity in male tree shrews.     

Methods of collection for salivary cortisol measurement in dogs

Salivary cortisol has been increasingly used as a measure of stress response in studies of welfare, reaction to stress and human-animal interactions in dogs and other species. While it can be a very useful measure, there are a number of saliva collection issues made evident through studies in the human and animal fields which have not been investigated in the canine species. Collection materials and the volume of saliva that is collected; the use of salivary stimulants; and the effect of food contamination can all dramatically impact cortisol measurement, leading to spurious results. In order to further examine the limitations of the collection method and the effects of collection material and salivary stimulant on salivary cortisol levels, a series of clinical, in vitro and in vivo studies were performed. It was found that there is a large amount of inter- and intra-individual variation in salivary cortisol measurement. Beef flavoring of collection materials leads to unpredictable variability in salivary cortisol concentration. Using salivary stimulants such as citric acid also has the potential to affect cortisol concentration measurement in saliva. Hydrocellulose appears to be a useful collection material for salivary cortisol determination. Recommendations for collection materials and use of salivary stimulants are presented.     

Saliva and serum cortisol dynamics following intravenous dexamethasone in normal volunteers

In order to further explore the utility of saliva cortisol as an accurate measure of adrenal steroid production, dexamethasone (DEX) and saline were administered intravenously at 0800h to eight normal male volunteers in a randomized design, and the effects on serum and saliva cortisol concentrations were measured at hourly intervals from 0800h-2300h. Saliva cortisol values were highly correlated to serum cortisol levels within-subjects under both conditions (r = 0.78, p less than 0.025), however correlations were reduced in the DEX day sample pairs. Across-subject correlations at each time point were considerably more variable, reflecting interindividual differences in the saliva to serum cortisol ratios. No consistent time lag of saliva cortisol values in response to serum cortisol fluctuations was observed. These data suggest that saliva cortisol is an excellent index of changes in adrenal production of cortisol over time within individuals; however, it also suggests that salivary cortisol measures have less usefulness in comparing values across groups of individuals.     

Salivary concentration of progesterone and cortisol significantly differs across individuals after correcting for blood hormone values

Between‐individual variation of salivary progesterone (P4) and cortisol levels does not always closely reflect blood hormone concentrations. This may be partly a function of individual differences in salivary hormone excretion. We tested whether time of day at sampling and ethnicity contributed to individual variation in salivary hormones after adjusting for blood hormone levels. Forty‐three Caucasian and 15 Japanese women (18–34 years) collected four sets of matched dried blood spot (DBS) and saliva specimens across a menstrual cycle (N = 232 specimen sets). Linear fixed‐effects (LFE) models were used to estimate the effects of diurnal variation and ethnicity on salivary P4 and cortisol while adjusting for DBS levels. For each hormone, women with exclusively positive or negative residuals (unexplained variance) from the LFE models were categorized as high‐ or low‐saliva‐to‐DBS hormone ratio (SDR; high or low salivary secretors), respectively. We found that salivary P4 (P < 0.05) was significantly higher in early morning compared to the afternoon, after controlling for DBS levels, ethnicity, and BMI. After further adjusting for this diurnal effect, significant individual variation in salivary P4 and cortisol remained: sixteen and nine women, respectively were categorized as low or high salivary secretors for both hormones (P < 0.001), suggesting systematic individual‐specific variation of salivary hormonal concentration. We conclude that when saliva is used to quantify P4 or cortisol levels, time of day at sampling should be controlled. Even with this adjustment, salivary P4 and cortisol do not closely mirror between‐ individual variation of serum P4 and cortisol in a substantial proportion of individuals. Am J Phys Anthropol 149:231–241, 2012. © 2012 Wiley Periodicals, Inc.     

Effect of coca-leaf chewing on salivary progesterone assays

Although there is evidence for reduced fertility in Andean and Himalayan populations at higher altitudes, factors other than hypoxia may be primarily responsible. A valuable approach in the investigation of these fertility determinants is the use of salivary steroid assays. However, coca-leaf chewing—a ubiquitous practice among high altitude Andean populations—has negative consequences for the accurate measurement of ovarian steroids. This report evaluates the effects of coca-leaf chewing on assays of salivary progesterone. Study participants include naive and habitual users of coca leaf from La Paz and El Alto, Bolivia. Approximately 300 saliva samples were collected immediately before, during, and after coca-leaf chewing. The series includes samples with and without the alkaloid enhancer typically used by coca-leaf chewers. Coca chewing produces false salivary progesterone values that mimic luteal phase values. On the basis of this study, an appropriate protocol is developed for the collection of salivary samples in coca-leaf chewing populations. These results verify the feasibility of salivary assays, even for very difficult field conditions, and highlight the necessity of establishing suitable collection procedures before full field implementation of saliva sampling. © 1993 Wiley-Liss, Inc.     

Salivary cortisol in low dose (1 microg) ACTH test in healthy women: comparison with serum cortisol

To date, a single report has appeared on the use of salivary cortisol for adrenal function testing with a low dose ACTH, although 1 microg has become preferred as a more physiological stimulus than the commonly used 250 microg ACTH test. Our present study was aimed to obtain physiological data on changes of free salivary cortisol after 1 microg ACTH stimulation. This approach was compared with the common method based on the changes of total serum cortisol. Intravenous, low-dose ACTH test was performed in 15 healthy women (aged 22-40 years) with normal body weight, not using hormonal contraceptives, in the follicular phase of the menstrual cycle. Blood and saliva for determination of cortisol were collected before ACTH administration and 30 and 60 min after ACTH administration. Basal concentration of salivary cortisol (mean +/- S.E.M., 15.9+/-1.96 nmol/l) increased after 1 microg ACTH to 29.1+/-2.01 nmol/l after 30 min, and to 27.4+/-2.15 nmol/l after 60 min. The differences between basal and stimulated values were highly significant (p<0.0001). The values of salivary cortisol displayed very little interindividual variability (p<0.04) in contrast to total serum cortisol values (p<0.0001) A comparison of areas under the curve (AUC) related to initial values indicated significantly higher AUC values for salivary cortisol than for total serum cortisol (1.89+/-0.88 vs. 1.22+/-0.19, p<0.01). Correlation analysis of serum and salivary cortisol levels showed a borderline relationship between basal levels (r=0.5183, p=0.0525); correlations after stimulation were not significant. Low-dose ACTH administration appeared as a sufficient stimulus for increasing salivary cortisol to a range considered as a normal adrenal functional reserve.     

Changes in adrenal and testicular activity monitored by salivary sampling in males throughout marathon runs

Measurement of cortisol and testosterone in saliva samples provided by marathon runners at 6.4 km (4-mile) intervals has been used for monitoring acute changes in adrenal and testicular activity, and the changes compared with mean values in timed samples on five rest days. The collection of mixed whole saliva was well accepted; the missed sample rate in the 8 runners in the Cardiff marathon was less than 10%. On rest days, salivary cortisol and testosterone were within the normal male range and showed a circadian rhythm; mean values at 08.00 h (23.5 nmol L-1; 258 pmol L-1, p less than 0.001, p less than 0.001 respectively) were higher than at 22.00 h (2.8 nmol L-1; 130 pmol L-1). In samples collected at 09.00 h, immediately prior to the Cardiff marathon, cortisol (25.1 nmol L-1) and testosterone (304 pmol L-1) were higher than the mean values (14.9 nmol L-1; 209 pmol L-1) on non-run days. Concentrations of both steroids increased during the marathon; testosterone peaked (442 pmol L-1) at 21 miles, whereas cortisol continued to increase, being maximal (87.9 nmol L-1) at 30 min after completion of the run. Four of the runners in the Cardiff marathon also participated in the Bristol marathon and the changing patterns in salivary hormones were strictly comparable. Salivary sampling would appear to be of value in monitoring acute and rhythmic changes in endocrine function in marathon runners. The temporal relationship between changes in salivary cortisol and testosterone are consistent with direct inhibition of testicular secretion by high cortisol concentrations.     

Bioluminescence immunoassay for cortisol using recombinant aequorin as a label

The analysis of hormones in saliva is a powerful tool in the assessment of a patient's endocrine function, since it allows multiple noninvasive samplings. Since salivary levels of most hormones are 10 to 50 times lower than plasma levels, accurate and highly sensitive assays are needed for saliva measurements. Herein, we describe the development of a solid-phase competitive immunoassay for cortisol in saliva, in which a mutant of the photoprotein aequorin has been used as a label. We have chemically conjugated cortisol to aequorin at different molar ratios. The various cortisol-aequorin conjugates were characterized in terms of bioluminescent activity and affinity for the anti-cortisol antibody. The conjugate that gave the best analytical performance was used for the development of the immunoassay and the analysis of cortisol in saliva samples. The conjugates were stable for at least 6 months when stored at 4 degrees C. The method fulfilled all the standard requirements of precision and accuracy. The optimized immunoassay gave a detection limit of 300 fmol/tube, corresponding to 3 nmol/L, with a linear dynamic range of 10-1000 nmol/L. Therefore, cortisol can be detected down to 0.1 ng in 100 microl of saliva sample using this assay, without any sample pretreatment. This detection limit is almost one order of magnitude lower than the physiological levels of salivary cortisol, which are reported to be 10-25 nmol/L. This allows the quantification of salivary cortisol to be performed in the linear range of the calibration curve, which is most reliable for quantification purposes.     

Noninvasive technique for the repeated sampling of salivary free cortisol in awake,unrestrained squirrel monkeys

The use of noninvasive measures of hypothalamic-pituitary-adrenal (HPA) axis function is of growing interest among preclinical and clinical investigators. This report describes a method for the repeated assessment of salivary free cortisol in awake, unrestrained squirrel monkeys (Saimiri sciureus) based on a saliva sampling technique previously developed for rhesus monkeys. Individually housed adult male squirrel monkeys were trained to chew on dental rope attached to a pole, from which saliva was extracted by centrifugation and analyzed for cortisol by radioimmunoassay (RIA). Eight of nine monkeys readily acquired the task, reliably providing adequate saliva samples for the assay. Salivary free cortisol levels were examined in these subjects under basal conditions and in response to two types of neuroendocrine challenge. Levels of salivary free cortisol showed relatively low intra- and interindividual variability, with mean individual morning levels ranging between 17.1 and 37.9 microg/dl. Squirrel monkeys demonstrated a consistent daily rhythm in salivary free cortisol ranging from a high of 27.4 +/- 5.2 microg/dl (mean +/- SEM) at 12 P.M. to a low of 7.5 +/- 1.6 microg/dl at 6 P.M. Intravenous (IV) challenges with 1 microg/kg ACTH, or 10 and 50 microg/kg CRF resulted in significant increases in salivary free cortisol. The described sampling technique provides a reliable and sensitive means for repeated measurement of HPA activity in unrestrained, awake squirrel monkeys. In addition, our findings illustrate several features of HPA system rhythmicity and reactivity using salivary cortisol instead of blood plasma or serum.     

Dexamethasone in resting and exercising men. II. Effects on adrenocortical hormones.

This study presents the reactions of adrenocorticosteroids (cortisol and aldosterone) and sex steroids [testosterone, androstenedione, and dehydroepiandrosterone and its sulfate (DHAS)] 1) to a dexamethasone (Dex) treatment, which is expected to lower steroid levels via the ACTH blockade, and 2) to an exercise bout at maximal O(2) consumption, which is expected to increase steroid production via ACTH stimulation. Consistent with the decrease in ACTH, all steroids except testosterone reacted negatively to Dex, independently of the dose (0.5 and 1.5 mg administered twice daily for 4.5 days). After exercise, plasma ACTH rose to 600% of basal value, resulting in a significant increase in aldosterone and adrenal androgens, but cortisol and DHAS were unaffected. This apparently surprising result can be explained by differences in peripheral metabolism: a theoretical calculation predicted that after 15 min the increase in hormone concentration may only reach 12% for cortisol and 2% for DHAS. For cortisol and adrenal androgens, assays were carried out using plasma and saliva. The consistent results obtained from the two matrices allow us to consider salivary assays as a useful tool for steroid abuse detection.     

Progesterone metabolism in human saliva in vitro.

Human salivary glands are known to be able to metabolize progesterone as well as other steroid hormones. The rate of progesterone metabolism in the salivary glands is so low that it is not thought to affect salivary progesterone concentrations. On the other hand it is usually recommended that saliva should be frozen quickly after the collection to prevent any kind of metabolism in saliva. When saliva is collected at home e.g. delayed freezing or partial thawing during to transport to laboratory may create circumstances where progesterone metabolism may occur. However, it is not known to which extent progesterone metabolism continues in saliva and whether this continued metabolism of progesterone affects salivary hormone levels. Paraffin-stimulated salivary samples were collected from female (N = 6) and male (N = 6) dental students and perimenopausal women (N = 8). The salivary samples were incubated with 14C-progesterone for 2 h at 37 degrees C in a shaking water bath. Metabolites were analyzed using thin-layer chromatography and autoradiography and quantified by liquid scintillation counting. Human saliva was found to be able to metabolize progesterone, but its metabolic activity was very low, 9.3 and 6.8 pmol/ml/h in young adults and perimenopausal women, respectively. Metabolic activity was higher in whole saliva than in the corresponding activities of the supernatant or sonicated fraction of the same saliva. The supernatant fraction, which was thought to be mainly representative of glandular saliva, was metabolically least active. The polar metabolites of progesterone predominated in all incubations. The metabolic activity of saliva is probably mainly due to its cellular content and the contribution of this activity to salivary progesterone concentrations is not significant.     

Diurnal variation on the excretion patterns of fecal steroids in common marmoset (Callithrix jacchus) females

The use of fecal steroid analysis to assess gonadal and adrenal function in primates has rapidly increased in recent years due to the ability to collect feces from nonhuman primates living in wild conditions. These techniques offer an exciting new potential for enhancing our knowledge of the endocrine status of free-living animals. Prior to using these techniques under field conditions, it is important to determine the diurnal variation of fecal excreted steroids for assessing possible time limitations on fecal collections. The following study investigates the diurnal frequency of defecation and patterns of steroid levels excreted in feces from four female common marmosets, Callithrix jacchus, living in a family group. These females represented three reproductive conditions: early pregnancy, ovarian cycling, and noncycling (postpubertal). Cortisol, estradiol, and progesterone were extracted and analyzed by enzyme immunoassay. Diurnal variations in steroid levels were found by ANOVA for cortisol and progesterone but not for estradiol. Significantly higher levels of cortisol were found in the afternoon, while the reverse was found for progesterone. All females showed the same pattern of steroid level change, except for cortisol in the pregnant female. Since all females defecated within the first hour after they awoke in the morning, this time was determined to be the most effective time to collect feces. The consistency of our findings reinforces the usefulness of this approach for studying reproductive and adrenocortical function in marmosets and also indicates that fecal collection should be limited to either morning or afternoon collections. Am. J. Primatol. 46:105–117, 1998. © 1998 Wiley-Liss, Inc.     

Adrenal steroidogenesis in the guinea pig: effects of androgens.

In humans, the onset of adrenache has been found to occur with the appearance of the zona reticularis, the inner zone of the adrenal cortex. Since an increase in the volume of adrenal cortex during maturation in the guinea pig has been associated with the growth of the zona reticularis, we were interested in investigating the changes in adrenal steroidogenesis during maturation in this species. In addition, the effect of androgens on adrenal steroidogenesis was studied. We demonstrated that between 1 and 10 weeks of age, a period of maximal growth of the adrenals in the guinea pig, there is a decrease in the concentrations of adrenal pregnenolone, cortisol, dehydroepiandrosterone, testosterone, androstenedione, and 11 beta-hydroxyandrostenedione, suggesting lower steroid production by the guinea pig adrenals. In plasma, we observed that the concentration of 11 beta-hydroxyandrostenedione (the sole C19 steroid present after castration) remained unchanged during maturation, while cortisol and corticosterone were lower between 1 and 4 weeks of age. Although castration as well as the administration of the antiandrogen flutamide had no effect on adrenal steroidogenesis, dihydrotestosterone caused an inhibition of cortisol and corticosterone levels in the adrenals while the concentrations of progestins (namely, pregnenolone, 17-hydroxypregnenolone, progesterone, and 17-hydroxyprogesterone) tended to increase in the adrenals, thus suggesting that dihydrotestosterone induces a blockade in the steroidogenic pathway.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of ACTH (tetracosactide) on steroid hormone levels in the mare. Part A: effect in intact normal mares and mares with possible estrous related behavioral abnormalities

Ovariectomized mares and mares with inactive ovaries may show signs of estrus. The reason behind this phenomenon is not clear; however, steroid hormones of adrenal origin have been suggested. Moreover, aberrant adrenal hormone production has been implied as a reason why some intact mares may change behavior. In the present study, the effect of ACTH on plasma levels of cortisol, progesterone, androstenedione and testosterone was investigated in intact mares with normal estrous behavior ('controls', n=5) and intact mares that according to their owners showed deviant estrous behavior ('problem' mares, n=7). Blood samples were collected hourly from 12:00 h until 14:00 h the following day (half-hourly between 14:00 and 17:00 h) on two occasions (at two estruses), with saline or ACTH treatment (tetracosactide) at 14:00 h (saline treatment day or ACTH treatment day). ACTH treatment caused a significant increase in plasma levels of cortisol, progesterone, androstenedione and testosterone in all mares (P<0.05). An overall significant difference in cortisol response to ACTH was found (P<0.05), with 'problem' mares showing a significantly lower increase in cortisol levels 30 min to 3h post ACTH treatment (P<0.001). The 'problem' mares also showed a significantly higher increase than controls in progesterone levels in the same time period (P<0.05). The reason for the reduced adreno-cortical reactivity, with a low cortisol response to the ACTH treatment, in the 'problem' mares is unknown, but may indicate a difference in adrenal function as compared to control mares.     

The measurement of hormones in saliva: possibilities and pitfalls

The easy stress-free, non-invasive nature of saliva collection makes it one of the most accessible body fluids and it is potentially of value in studying normal human physiology as well as pathology. Measurements of salivary hormone levels will usually only be of value if they reflect the plasma level of the hormone and the relationship between the saliva and plasma levels of many hormones have been studied by a number of groups. The measurement of the salivary level is a valuable clinical tool for some hormones (e.g. cortisol, oestriol, progesterone), is of little value for others (e.g. cortisone, dehydroepiandrosterone sulphate, thyroxine, pituitary hormones) and for many others the saliva/plasma relationship is not yet sufficiently understood to assess the value of the salivary measurement. As well as reviewing the state of our knowledge of the salivary concentration of many hormones this review outlines a number of "rules of thumb" concerning the presence of hormones in saliva, their saliva/plasma relationship and the potential usefulness of assays of their salivary concentration.     

Diagnostic value of salivary cortisol in children with abnormal adrenal cortex functions

AIMS: It has been shown that the free cortisol level in saliva may reflect plasma free cortisol. The measurement of cortisol in saliva is a simple method, and as such it is important in the pediatric age group. In this research, the diagnostic value of measurement of salivary cortisol (SC) measurement was examined in adrenal insufficiency (AI). METHODS: Fifty-one patients, mean age 10.8 +/- 4.29, who were investigated for possible AI, were included. Basal cortisol levels were below 18 microg/dl. Adrenal function was determined by low-dose ACTH test. During the test, samples for SC were obtained simultaneously with serum samples (at 0-10-20-30-40 min). RESULTS: Mean basal serum cortisol level was 8.21 +/- 4.10 microg/dl (mean +/- SD). Basal SC was correlated to basal serum cortisol (r = 0.64, p < 0.001). A cut-off of 0.94 microg/dl for SC differentiated adrenal insufficient subjects from normals with a sensitivity and specificity of 80 and 77%, respectively. A peak SC less than 0.62 microg/dl defined AI with a specificity of 100%; however, sensitivity was 44%. CONCLUSION: Measurement of SC may be used in the evaluation of AI. It is well-correlated to serum cortisol. Peak SC in low-dose ACTH test can be used to differentiate patients with AI in the initial evaluation of individuals with suspected AI.     

Effect of chewing betel nut on measurements of salivary progesterone and estradiol

The measurement of steroids in saliva is both simple and non-invasive and has been widely used in field and clinical-based research. The observance of particular cultural practices by some populations, however, may hamper accurate hormonal analyses. The present study evaluated the effects of one such practice-the chewing of betel nut-on the accurate measurement of salivary progesterone and estradiol. A time series experiment was conducted among Bangladeshi women who are regular users of betel nut. Salivary steroids were analyzed by radioimmunoassay in samples collected prior to and then 30, 60, 120, and 240 min following betel quid use. Results show no significant difference between basal steroid levels and those obtained 60, 120, and 240 min after chewing betel nut. We conclude that with specific collection protocols that take into account time since chewing, salivary steroid analyses can be undertaken in populations among whom the practice of chewing betel nut is endemic.     

Conditions for assessing cortisol in sheep: the total form in blood v. the free form in saliva

Cortisol is often used as a stress indicator in animal behaviour research. Cortisol is commonly measured in plasma and can also be measured in saliva. Saliva contains only the free form of cortisol, which is biologically active, and saliva sampling is not invasive and may therefore be less stressful. Our study aims to guide the choice between the measurements of cortisol in plasma v. saliva depending on experimental conditions. We analysed the effect of the level of cortisol in plasma on the concentration of cortisol in saliva compared to plasma and the effect of saliva sampling v. jugular venepuncture on the cortisol response. In Experiment 1, blood and saliva were collected simultaneously under conditions in which the expected cortisol release in blood varied: in an undisturbed situation or after the isolation of lambs from their pens or the administration of exogenous ACTH (six animals per treatment). In Experiment 2, we subjected lambs to saliva sampling, venepuncture or neither of these for 8 days to evaluate how stressful the sampling method was and whether the animals habituated to it by comparing the responses between the first and last days (four animals per treatment). All animals were equipped with jugular catheters to allow regular blood sampling without disturbance. Samples were collected 15 min before any treatment was applied, then at various time points up to 135 min in Experiment 1 and 45 min in Experiment 2. In Experiment 1, we observed a strong correlation between salivary and plasma cortisol concentrations (r = 0.81, P < 0.001). The ratio between salivary and plasma cortisol concentrations was 0.106 on average. This ratio was higher and more variable when the cortisol concentration in plasma was below 55 nmol/l. In Experiment 2, venepuncture induced a larger cortisol response than saliva sampling or no intervention on day 1 (P < 0.02); this difference was not observed on day 8, suggesting that sheep habituated to venepuncture. We recommend the measurement of cortisol in saliva to avoid stressing animals. However, when the expected concentration in plasma is below 55 nmol/l, the cortisol in saliva will reflect only the free fraction of the cortisol, which may be a limitation if the focus of the experiment is on total cortisol. In addition, if cortisol is measured in plasma and blood is collected by venepuncture, we recommend that sheep be habituated to venepuncture, at least to the handling required for a venepuncture.     

Steroid-protein interaction in human placenta

Human placenta produces a large variety of bioactive substances with endocrine and neural competence: pituitary and gonadal hormones, hypothalamic-like releasing or inhibiting hormones, growth factors, cytokines and neuropeptides. The most recent findings indicate that locally produced hormones regulate the secretion of other placental hormones supporting a paracrine/autocrine regulation. In placental endocrinology, a particular relevance is played by steroid hormones. In fact, a specific gonadotropin-releasing hormone (GnRH)-human chorionic gonadotropin (hCG) regulation of placental steroidogenesis has been proposed as a placental internal regulatory system acting on steroids production from human placenta. In addition, activin and inhibin have been proposed as further regulatory substances of the synthesis and secretion of steroids; the addition of activin A to placental culture augments GnRH, hCG and progesterone, and this effect can be significantly reduced by the addition of inhibins. Finally, a steroid-steroid interaction is suggested by the evidence that placental estrogen has a positive role in the regulation of progesterone biosynthesis. Other steroid-protein interactions have been observed in human placenta. In fact, recent data indicate that progesterone inhibits placental corticotropin-releasing factor (CRF) and estrogens act on placental conversion of cortisol to cortisone, activating cortisol secretion by the fetal adrenal and enhancing fetal adrenal function with advancing gestation.     

Salivary progesterone for the assessment of the ovarian function in the capuchin monkey (Cebus apella)

Salivary and plasma progesterone were measured in normally cycling (n=10) and castrated (n=4) femaleCebus monkeys (Cebus apella). During the follicular phase, progesterone levels in saliva ranged between 0.05 and 1.40 ng/ml and in the luteal phase they increased to between 0.22 and 4.70 ng/ml. These values represented on average 6.5 and 3.2% of those values measured in plasma, for the follicular and luteal phases, respectively. The regression analysis of the steroid concentrations in both fluids showed a highly significant correlation (r=0.8985,n=180,P<0.0001). Ovariectomized monkeys had consistently low salivary (0.37±0.02 ng/ml) and plasma (4.70±0.25 ng/ml) progesterone, showing a low, but significnat, correlation coefficient (r=0.2592,n=58,P=0.047). The ratio of plasma/salivary progesterone was significantly higher in the luteal phase (31.09±1.65) than in the follicular phase (23.06±2.26) and in castrated monkeys (16.00±1.38). The free fraction of progesterone constituted 5.3±0.2% of the total plasma progesterone during the follicular phase and 3.3±0.1% during the luteal phase. Ovariectomized monkeys showed a significantly higher percentage of free progesterone in plasma (7.7±0.1%). In contrast, free progesterone made up 64.4 and 70.9% of the total salivary progesterone for the follicular and luteal phases, respectively. The proportion of free progesterone in castrated animals was within the range observed in cycling animals. We suggest that the levels of progesterone in the saliva of capuchin monkey follow a pattern similar to that for plasma progesterone, reflecting the free steroid fraction. Thus, the measurement of such steroid in saliva may offer a valuable alternative to plasma determinations for the assessment of the ovarian function inCebus and probably other New World monkey species.