Measuring steroids in hair opens up possibilities to identify congenital adrenal hyperplasia in developing countries

OBJECTIVE

Patients with congenital adrenal hyperplasia (CAH) in developing countries have limited access to appropriate laboratory facilities for diagnosis and follow-up. The aim of this study is to evaluate steroid measurement in hair as a diagnostic tool to identify and monitor CAH in these patients.

DESIGN

A method was developed to measure steroids in hair, the stability of steroids in hair was assessed, and the concentration range in healthy volunteers was determined. Hair samples of patients, before and after starting therapy, were transported at ambient temperature to The Netherlands for analysis.

PATIENTS

Twenty-two Indonesian CAH patients and 84 healthy volunteers participated.

MEASUREMENTS

Cortisol, 17-hydroxyprogesterone (17OHP), androstenedione, and testosterone in hair were measured by liquid chromatography with tandem mass spectrometry.

RESULTS

Steroids in hair could be measured and remained stable (<4.9% deviation) for at least 3 weeks at 4°C and 30°C. In each of the untreated patients, hair concentrations of 17OHP (9.43-1135 pmol/g), androstenedione (36.1-432 pmol/g), and testosterone (2.85-69.2 pmol/g) were all above the upper limit of the corresponding range in healthy volunteers; 5.5 pmol/g, 13 pmol/g, and 1.8 pmol/g, respectively. After starting glucocorticoid treatment, the steroid concentrations in the hair of CAH patients decreased significantly for androstenedione (73%) and testosterone (59%) after 6 months.

CONCLUSIONS

CAH could be confirmed in Indonesian patients based on the concentration of 17OHP, androstenedione, and testosterone in hair, and a treatment effect was observed. These findings open up opportunities to diagnose and/or monitor CAH in developing countries with a simple noninvasive technique.

Glucocorticoid Activity of Adrenal Steroid Precursors in Untreated Patients With Congenital Adrenal Hyperplasia

CONTEXT AND OBJECTIVE

We describe the clinical features and biochemical characteristics of a unique population of severely affected untreated patients with congenital adrenal hyperplasia (CAH) from an Indonesian population with proven cortisol deficiency but without clinical signs of cortisol deficiency. We evaluated the in vitro glucocorticoid activity of all relevant adrenal steroid precursors occurring in patients with CAH.

DESIGN

Cross-sectional cohort study and translational research.

INTERVENTION/MAIN OUTCOME MEASURES

Adrenal steroid precursor concentrations before and 60 minutes after ACTH administration to 24 untreated patients with CAH (3 to 46 years) with proven cortisol deficiency (<500 nmol/L post-ACTH) measured by liquid chromatography-tandem mass spectrometry were compared with six control patients (Mann-Whitney U test). Glucocorticoid receptor (GR) activation was determined by dual-luciferase assays in human embryonic kidney cells transfected with the GR and exposed to increasing amounts of adrenal steroid precursors for 24 hours.

RESULTS

Blood concentrations of the steroid precursors 11-deoxycortisol (457 nmol/L, P = 0.003), 11-deoxycorticosterone (55 nmol/L, P = 0.003), 17-hydroxyprogesterone (610 nmol/L, P < 0.001), progesterone (29 nmol/L, P < 0.001), and 21-deoxycortisol (73 nmol/L) were strongly elevated compared with control subjects. The GR was activated with comparable potency to cortisol by corticosterone and 21-deoxycortisol or with 4 to 100 times lower potency by 11-hydroxyprogesterone, 11-deoxycortisol, aldosterone, 11-deoxycorticosterone, progesterone, and 17-hydroxyprogesterone.

CONCLUSIONS

We identified strongly elevated adrenal steroid precursor concentrations in blood from untreated patients with CAH and demonstrated glucocorticoid activity of these adrenal precursors in vitro, suggesting a possible role of these precursors in the clinical phenotype of these patients. Further studies are necessary to evaluate the role of these precursors in more detail.

Elevated Serum Endothelin-1 Levels in Patients with Colorectal Cancer; Relevance for Prognosis

Background

It has been demonstrated that the Doppler Perfusion Index (DPI) is increased in patients who are at risk of developing liver metastases from colorectal cancer. It has been postulated that a circulating hormonal factor is involved in the relative vasoconstriction throughout the splanchnic bed. Endothelin-1 (ET-1), a potent vasoconstrictor which has been associated with tumor growth and is produced by colorectal tumors, may play an important role in this phenomenon. In this paper the prognostic value of serum ET-1 in colorectal cancer is discussed.

Methods

Preoperative serum levels of ET-1 were assessed in three groups of patients: group A underwent resection of the colorectal tumor and remained free of recurrence (n=20); group B developed metachronous liver metastases at least six months after colorectal resection (n=14); and group C presented with colorectal cancer and synchronous liver metastases (n=22).

Results

The mean (SD) serum ET-1 levels in groups A, B and C were 1.59 (0.41) pmol/L, 1.70 (0.32) pmol/L and 1.85 (0.47) pmol/L, respectively. These values were significantly different from those of healthy controls (1.22 (0.31), p<0.05). Kaplan-Meier analyses revealed no prognostic value of preoperative serum ET-1 levels.

Conclusions

These preliminary results demonstrate that serum ET-1 levels are raised in patients with colorectal cancer. Serum ET-1 levels do not seem to be of prognostic value for survival.

Gonadal function in adult male patients with congenital adrenal hyperplasia

CONTEXT

Current knowledge on gonadal function in congenital adrenal hyperplasia (CAH) is mostly limited to single-center/country studies enrolling small patient numbers. Overall data indicate that gonadal function can be compromised in men with CAH.

OBJECTIVE

To determine gonadal function in men with CAH within the European 'dsd-LIFE' cohort.

DESIGN

Cross-sectional clinical outcome study, including retrospective data from medical records.

METHODS

Fourteen academic hospitals included 121 men with CAH aged 16-68 years. Main outcome measures were serum hormone concentrations, semen parameters and imaging data of the testes.

RESULTS

At the time of assessment, 14/69 patients had a serum testosterone concentration below the reference range; 7 of those were hypogonadotropic, 6 normogonadotropic and 1 hypergonadotropic. In contrast, among the patients with normal serum testosterone (55/69), 4 were hypogonadotropic, 44 normogonadotropic and 7 hypergonadotropic. The association of decreased testosterone with reduced gonadotropin concentrations (odds ratio (OR) = 12.8 (2.9-57.3)) was weaker than the association between serum androstenedione/testosterone ratio ≥1 and reduced gonadotropin concentrations (OR = 39.3 (2.1-732.4)). Evaluation of sperm quality revealed decreased sperm concentrations (15/39), motility (13/37) and abnormal morphology (4/28). Testicular adrenal rest tumor (TART)s were present in 39/80 patients, with a higher prevalence in patients with the most severe genotype (14/18) and in patients with increased current 17-hydroxyprogesterone 20/35) or androstenedione (12/18) serum concentrations. Forty-three children were fathered by 26/113 patients.

CONCLUSIONS

Men with CAH have a high risk of developing hypothalamic-pituitary-gonadal disturbances and spermatogenic abnormalities. Regular assessment of endocrine gonadal function and imaging for TART development are recommended, in addition to measures for fertility protection.

Do blood plasma levels of oxytocin moderate the effect of nasally administered oxytocin on social orienting in high-functioning male adults with autism spectrum disorder?

OBJECTIVE

The study investigated whether baseline plasma oxytocin (OXT) concentrations might moderate the effects of nasally administered OXT on social orienting.

METHODS

Thirty-one males with Autism spectrum disorder (ASD) and thirty healthy males participated in a double-blind placebo-controlled crossover trial. After administration of the compound, participants were viewing pictures from the International Affective Picture System that represented a systematic variation of pleasant, unpleasant and neutral scenes with and without humans. The outcome measures were a cardiac evoked response (ECR) and a cortical evoked long latency parietal positivity (LPP).

RESULTS

Males with ASD had significantly higher plasma baseline levels than the controls. In the absence of general treatment effects, higher baseline concentrations were found to be associated with larger treatment effects, particularly in the group of males with ASD. Higher post-treatment plasma OXT concentrations were found to be associated with smaller treatment effects and larger orienting responses in the placebo situation in the group of controls.

CONCLUSIONS

We interpret our findings as suggesting that it is the central availability of OXT determining how much of the nasally administered OXT will become centrally absorbed and how much of it will become released into the bloodstream.

Identification of novel genetic Loci associated with thyroid peroxidase antibodies and clinical thyroid disease

Autoimmune thyroid diseases (AITD) are common, affecting 2-5% of the general population. Individuals with positive thyroid peroxidase antibodies (TPOAbs) have an increased risk of autoimmune hypothyroidism (Hashimoto's thyroiditis), as well as autoimmune hyperthyroidism (Graves' disease). As the possible causative genes of TPOAbs and AITD remain largely unknown, we performed GWAS meta-analyses in 18,297 individuals for TPOAb-positivity (1769 TPOAb-positives and 16,528 TPOAb-negatives) and in 12,353 individuals for TPOAb serum levels, with replication in 8,990 individuals. Significant associations (P<5×10(-8)) were detected at TPO-rs11675434, ATXN2-rs653178, and BACH2-rs10944479 for TPOAb-positivity, and at TPO-rs11675434, MAGI3-rs1230666, and KALRN-rs2010099 for TPOAb levels. Individual and combined effects (genetic risk scores) of these variants on (subclinical) hypo- and hyperthyroidism, goiter and thyroid cancer were studied. Individuals with a high genetic risk score had, besides an increased risk of TPOAb-positivity (OR: 2.18, 95% CI 1.68-2.81, P = 8.1×10(-8)), a higher risk of increased thyroid-stimulating hormone levels (OR: 1.51, 95% CI 1.26-1.82, P = 2.9×10(-6)), as well as a decreased risk of goiter (OR: 0.77, 95% CI 0.66-0.89, P = 6.5×10(-4)). The MAGI3 and BACH2 variants were associated with an increased risk of hyperthyroidism, which was replicated in an independent cohort of patients with Graves' disease (OR: 1.37, 95% CI 1.22-1.54, P = 1.2×10(-7) and OR: 1.25, 95% CI 1.12-1.39, P = 6.2×10(-5)). The MAGI3 variant was also associated with an increased risk of hypothyroidism (OR: 1.57, 95% CI 1.18-2.10, P = 1.9×10(-3)). This first GWAS meta-analysis for TPOAbs identified five newly associated loci, three of which were also associated with clinical thyroid disease. With these markers we identified a large subgroup in the general population with a substantially increased risk of TPOAbs. The results provide insight into why individuals with thyroid autoimmunity do or do not eventually develop thyroid disease, and these markers may therefore predict which TPOAb-positives are particularly at risk of developing clinical thyroid dysfunction.

Catheter-based renal nerve ablation and centrally generated sympathetic activity in difficult-to-control hypertensive patients: prospective case series

Endovascular renal nerve ablation has been developed to treat resistant hypertension. In addition to lowering efferent renal sympathetic activation, the intervention may attenuate central sympathetic outflow through decreased renal afferent nerve traffic, as evidenced by a recent case report. We tested the hypothesis in 12 nonpreselected patients with difficult-to-control hypertension (aged 45-74 years) admitted for renal nerve ablation. All patients received ≥ 3 antihypertensive medications at full doses, including a diuretic. Electrocardiogram, respiration, brachial and finger arterial blood pressure, and muscle sympathetic nerve activity were recorded before and 3 to 6 months after renal nerve ablation. Heart rate and blood pressure variability were analyzed in the time and frequency domain. Pharmacological baroreflex slopes were determined using the modified Oxford bolus technique. Resting heart rate was 61 ± 3 bpm before and 58 ± 2 bpm after ablation (P = 0.4). Supine blood pressure was 157 ± 7/85 ± 4 mm Hg before and 157 ± 6/85 ± 4 mm Hg after ablation (P = 1.0). Renal nerve ablation did not change resting muscle sympathetic nerve activity (before, 34 ± 2 bursts per minute; after, 32 ± 3 bursts per minute P = 0.6), heart rate variability, or blood pressure variability. Pharmacological baroreflex control of heart rate and muscle sympathetic nerve activity did not change. We conclude that reduced central sympathetic inhibition may be the exception rather than the rule after renal nerve ablation in unselected patients with difficult-to-control arterial hypertension.

Genetic correction of PSA values using sequence variants associated with PSA levels

Measuring serum levels of the prostate-specific antigen (PSA) is the most common screening method for prostate cancer. However, PSA levels are affected by a number of factors apart from neoplasia. Notably, around 40% of the variability of PSA levels in the general population is accounted for by inherited factors, suggesting that it may be possible to improve both sensitivity and specificity by adjusting test results for genetic effects. To search for sequence variants that associate with PSA levels, we performed a genome-wide association study and follow-up analysis using PSA information from 15,757 Icelandic and 454 British men not diagnosed with prostate cancer. Overall, we detected a genome-wide significant association between PSA levels and single-nucleotide polymorphisms (SNPs) at six loci: 5p15.33 (rs2736098), 10q11 (rs10993994), 10q26 (rs10788160), 12q24 (rs11067228), 17q12 (rs4430796), and 19q13.33 [rs17632542 (KLK3: I179T)], each with P(combined) <3 × 10(-10). Among 3834 men who underwent a biopsy of the prostate, the 10q26, 12q24, and 19q13.33 alleles that associate with high PSA levels are associated with higher probability of a negative biopsy (odds ratio between 1.15 and 1.27). Assessment of association between the six loci and prostate cancer risk in 5325 cases and 41,417 controls from Iceland, the Netherlands, Spain, Romania, and the United States showed that the SNPs at 10q26 and 12q24 were exclusively associated with PSA levels, whereas the other four loci also were associated with prostate cancer risk. We propose that a personalized PSA cutoff value, based on genotype, should be used when deciding to perform a prostate biopsy.

External validation of serum hCG cutoff levels for prediction of resistance to single-agent chemotherapy in patients with persistent trophoblastic disease

Van Trommel et al have previously shown that serum human chorionic gonadotropin (hCG) cutoff levels can provide early prediction of resistance to first-line methotrexate (MTX) in patients with persistent trophoblastic disease (PTD). In this study, we validate this approach of prediction of resistance to single-agent chemotherapy in an independent and larger cohort of PTD patients using a different hCG assay. Receiver operating characteristics (ROC) curves were constructed to determine hCG cutoff levels and sensitivity between patients cured on single-agent chemotherapy (control group) and patients requiring change to combination chemotherapy (study group). Receiver operating characteristics analysis identified an hCG cutoff value of 737 IU l⁻¹ that enabled us to predict the subsequent development of single-agent chemotherapy resistance in 52% of patients before their fourth MTX course at 97.5% specificity. This would have enabled an earlier switch to combination chemotherapy reducing the MTX exposure by an average of 2.5 courses. The present findings confirm that serum hCG cutoff levels predict resistance to single-agent therapy earlier than traditional methods. Change to combination chemotherapy should be considered for patients whose serum hCG levels exceed these hCG cutoff values. For patients not exceeding the hCG cutoff levels, static or rising hCG levels should still be included in the criteria for change of chemotherapy.

Complex congenital malformations and the impact of the plasminogen activator system and beta-hCG in amniotic fluid

OBJECTIVE

The plasminogen activator system and beta-hCG may affect neural crest cells and angiogenesis, and thereby embryogenesis. Therefore, we investigated these parameters in amniotic fluids of pregnancies with a complex congenital malformation.

STUDY DESIGN

In a case-control study amniotic fluid samples were collected from 62 pregnancies with a complex congenital malformation and from 110 healthy control pregnancies at an obstetric department of a large university hospital in the Netherlands. We determined concentrations of tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), plasminogen activator inhibitors (PAI-1, PAI-2), tPA approximately PAI-1 and uPA approximately PAI-1 complexes, and beta-hCG with enzyme-linked immunosorbent assays. Mann-Whitney U-tests and analysis of covariance, adjusting for gestational and maternal age, were performed for data comparisons.

RESULTS

Compared with controls, cases demonstrated significantly lower adjusted geometric mean levels of uPA (24%), tPA (> or =19%) and tPA approximately PAI-1 (35%). Cases showed significantly higher adjusted mean levels of beta-hCG (> or =48%) and PAI-2 (10 ng/mL) than controls. Mean PAI-1 and uPA approximately PAI-1 levels were comparable between both groups.

CONCLUSIONS

Disturbances in the plasminogen activator system and beta-hCG levels are suggested to be involved in the pathogenesis of complex congenital malformations by affecting neural crest cell migration and angiogenesis.

Early Identification of Resistance to First-Line Single-Agent Methotrexate in Patients With Persistent Trophoblastic Disease

Purpose

A generally accepted definition for resistance to first-line single-agent chemotherapy for persistent trophoblastic disease (PTD) is lacking. In the present study, a normogram for serum human chorionic gonadotropin (hCG) from patients with normalization of serum hCG after first-line single-agent chemotherapy for PTD was constructed to identify patients resistant to this chemotherapy.

Patients and Methods

Between 1987 and 2004, data from 2,132 patients were registered at the Dutch Central Registry for Hydatidiform Moles. A normal serum hCG regression corridor was constructed for 79 patients with low-risk PTD who were cured by single-agent methotrexate (MTX) chemotherapy (control group). Another group of 29 patients with low-risk PTD needed additional alternative therapies (dactinomycin and multiagent chemotherapy) for failure of serum hCG to normalize with single-agent chemotherapy (study group).

Results

Serum hCG measurement preceding the fourth and sixth single-agent chemotherapy course proved to have excellent diagnostic accuracy for identifying resistance to single-agent chemotherapy, with an area under the curve (AUC) for receiver operating characteristic curve analysis of 0.949 and 0.975, respectively. At 97.5% specificity, serum hCG measurements after 7 weeks showed 50% sensitivity.

Conclusion

In the largest study to date, we describe the regression of serum hCG levels in patients with low-risk PTD successfully treated with MTX. At high specificity, hCG levels in the first few courses of MTX can identify half the number of patients who are extremely likely to need alternative chemotherapy to cure their disease and for whom further treatment with single-agent chemotherapy will be ineffective.

Plasminogen activator system in serum and amniotic fluid of euploid and aneuploid pregnancies

OBJECTIVE

To compare euploid and aneuploid pregnancies with respect to maternal serum and amniotic fluid (AF) levels of the components of the plasminogen system.

METHODS

The study population consisted of 123 single pregnancies at the 17th gestational week, 16 with minor chromosomal abnormalities, 15 aneuploid, and 92 euploid.

RESULTS

Both groups with chromosomal abnormalities had significantly higher serum levels of urokinase plasminogen activator and its complexed form with its type-1 inhibitor compared with euploid pregnancies. In AF, tissue plasminogen activator was significantly lower in the aneuploid than the euploid group, whereas type-1 inhibitor of plasminogen activator was significantly higher in the cases with minor chromosomal abnormalities compared with euploid. At cutoff levels set at 100% sensitivity, the complexed form of urokinase plasminogen activator with its type-1 inhibitor had the strongest specificity (66.3%); after logarithmic transformation, its serum level was 7.53 times higher in aneuploidies than euploidies.

CONCLUSION

Aneuploid pregnancies appear to be accompanied by abnormalities of the plasminogen activation system, which could lead to impaired placental perfusion and thus to abortion, fetal death, and fetal growth restriction.

Angiostatin generation by human tumor cell lines: involvement of plasminogen activators

Angiostatin is a tumor-derived angiogenesis inhibitor consisting of an internal fragment of plasminogen. Little is known about the production of angiostatin by human tumors. In this study, we examined the in vitro angiostatin-generating capacities of a panel of human tumor cell lines (total n = 75) and the proteolytic molecule(s) involved. Angiostatin formation was determined by assessing the level of plasminogen digestion in conditioned medium by Western-blot analysis. We found that the capacity to produce angiostatin is a common feature of many cell lines, depending on the tumor type. All 6 bladder-carcinoma and 6 out of 7 prostate-carcinoma cell lines showed intermediate to potent angiostatin-generating activity. In contrast, only 2 out of 7 colon-carcinoma and 2 out of 9 renal-cell carcinoma cell lines were able to generate angiostatin at intermediate levels. Out of 25 melanoma cell lines, only one line failed to generate angiostatin. In the other cell-line groups (cervix, breast and ovary), angiostatin formation varied. Remarkably, angiostatin bands were not of equal size in all plasminogen digests. Since reported data have indicated that plasminogen activators (uPA and tPA) were able to excise the angiostatin fragment from the plasminogen parent molecule via plasmin generation, we determined levels of uPA and tPA and PAI-1 antigen in the conditioned media, and correlated the results with angiostatin-generating capacity. Whereas prostate- and bladder-carcinoma lines capable of generating high levels of angiostatin showed high uPA levels, angiostatin generation in melanoma cell lines was correlated with tPA levels. Generally, angiostatin non-producers did not express uPA or tPA. In 6 out of 75 cell lines, however, we found angiostatin generation combined with low or absent levels of plasminogen activator, suggesting the involvement of alternative proteolytic pathways in the generation of angiostatin.

Immune responses to experimental stress: effects of mental effort and uncontrollability

OBJECTIVE

Two important determinants of physiological stress responses have been identified, uncontrollability of the stressor and amount of effort involved in coping with the stressor. In the present experiment, we tried to identify the specific contributions of effort and uncontrollability to immune system responses to stress.

METHODS

In a 2 x 2 design, effort and uncontrollability were manipulated independently of each other. Subjects participated in one of four experimental conditions, and their endocrine, immune, and sympathetic nervous system responses to the task were assessed.

RESULTS

Effort had a stimulating effect on enumerative immunological parameters (CD8 and CD16+ cells) and on natural killer cell activity. The effect occurred immediately after the stressor and was transient. Regression models indicated that this effort effect may have been mediated by activation of the sympathetic nervous system. Uncontrollability influenced in vitro production of the cytokine interleukin-6, leading to decreased production 15 and 30 minutes after the stressor. Uncontrollability also led to an increased level of cortisol, but no evidence was found that the decrease in cytokine production was mediated by cortisol release.

CONCLUSION

The results suggest that two major stressor characteristics, effort and uncontrollability, may have differential effects on the immune system.

A neuropeptide in human semen: oxytocin

The neuropeptide oxytocin (OT) has been detected in testis and epididymis of several mammals. The peptide affects steroidogenesis and sperm transport in vivo. Effects of OT on sperm motility in vitro seems to be contradictory. As no data are available on the presence of OT in human semen and on the relationship of OT with sperm characteristics, we assessed OT level in semen samples in 3 groups of patients: (I) normozoospermic, (II) astheno-/oligo-/teratozoospermic, and (III) azoospermic subjects. Furthermore, we studied the relationship between the concentration of OT in semen and the sperm characteristics. OT was measured in seminal plasma by radioimmunoassay after extraction. OT semen levels did not differ in control patients (I: 1.72 +/- 0.78 pg/mL; n = 10), patients with poor semen quality (II: 1.66 +/- 0.91 pg/mL; n = 11), or in vasectomized patients (III: 1.28 +/- 0.65 pg/mL; n = 11). No statistically significant relationships between the OT levels and sperm characteristics (density: 0.0693; total sperm count: 0.0845; percentage of motility: 0.1341; morphology: 0.3478) have been found. The neurosecretory peptide oxytocin is present in human seminal plasma of normal as well as of vasectomized subjects. OT is not only derived from the testis; OT levels in poor semen samples are not different from controls. No relationship was found between OT seminal plasma levels and sperm characteristics.

Cardiovascular and endocrine responses to experimental stress: effects of mental effort and controllability

The objective of the study was to investigate the unique and interactive effects of the controllability of a task and mental effort required by that task on cardiovascular and endocrine reactivity, when both were manipulated independently. A 2 x 2 factorial design was used, with two levels of mental effort and two levels of control. Twenty-four healthy male subjects participated in each experimental condition. Heart rate, blood pressure, catecholamine and cortisol responses were determined. High effort lead to greater increases in heart rate, blood pressure and norepinephrine levels. Uncontrollability lead to higher cortisol, blood pressure and norepinephrine responses. In addition, there was an effort x control interaction effect on the diastolic blood pressure response. In conclusion, effort has clear sympathetic effects, whereas control influences both the sympathetic nervous system and the release of cortisol. Having control seems to be most beneficial in high effort situations, at least with respect to sympathetic reactivity.

Bioavailability and pharmacokinetics of sublingual oxytocin in male volunteers

The aim of this investigation was to assess the bioavailability and pharmacokinetics of oxytocin in six male subjects after a sublingual dose of 400 int. units (684 micrograms) and after an intravenous dose of 1 int. unit (1.71 micrograms). After intravenous administration, the pharmacokinetic profile could be described with a two-compartment model. The distribution half-life was 0.049 +/- 0.106 h, the elimination half-life was 0.33 +/- 0.23 h, the total body clearance was 67.1 +/- 13.4 L h-1 and the volume of distribution was 33.2 +/- 28.1 L. After sublingual administration, a poor bioavailability with a 10-fold variation between 0.007 and 0.07% was observed. The pharmacokinetic profile could be described with a one-compartment model. The lag time was subject-dependent and ranged between 0.12 and 0.30 h (40% CV). The absorption half-life was 0.45 +/- 0.29 h, and the apparent elimination half-life 0.69 +/ - 0.26 h. This study showed a very poor and interindividual variability in bioavailability. The sublingual route of administration with its 'long' lag time and 'long' absorption half-life would not seem a reliable route for accurate high dosing for immediate prevention of post-partum haemorrhage.