Antisera were prepared against three related oestrogen ring-A glucuronides, oestrone 3-glucuronide, oestradiol 3-glucuronide and oestriol 3-glucuronide. The corresponding 6,7-3H-labelled conjugates were synthesized as radioligands and the cross-reactions of the antisera against ring-A oestrogen glucuronides and other steroid conjugates were examined. The specificity of the antiserum against oestriol 3-glucuronide was compared with that raised against oestriol 16alpha-glucuronide, and the measurement of the former conjugate in late-pregnancy urine is discussed.

A fluorometric liquid chromatographic method was developed for measurements of unconjugated oestradiol and oestriol in the serum of pregnant women. The serum samples are injected directly into the apparatus and pass to a pretreatment column, where oestrogens are adsorbed while hydrophilic components such as proteins and carbohydrates are not. The oestrogens then pass into a separation column containing a new type of polymer gel. The mobile phase consists of an acetonitrile-water mixture, and separation is achieved by a reversed-phase mechanism. The eluent is monitored for fluorescence. Data on the reproducibility and recovery by this method and the correlation of values with those obtained by radioimmunoassay are reported. Results on the increases of oestradiol and oestriol in the serum during pregnancy are also reported.

BACKGROUND

Fully breastfeeding women experience an amenorrhoea of variable duration. Our aim was to identify in pregnancy, endocrine markers that could predict the duration of subsequent lactational amenorrhoea.

METHODS

We studied 17 healthy women at 34 and 38 weeks gestation, and 1 and 3 months post-partum. The women fully breastfed until 6 months post-partum. During pregnancy, prolactin (PRL), oestrogens (total oestradiol, unconjugated oestrone, unconjugated oestriol), sex hormone binding globulin (SHBG), dehydroepiandrosterone sulphate (DHEA-S), progesterone and placental lactogen, and during post-partum PRL, oestrogens and SHBG, were measured. Free oestradiol in pregnancy and post-partum was calculated.

RESULTS

Ten women experienced long (>6 months) and seven experienced short (<6 months) lactational amenorrhoea. At 38 weeks gestation, the women who experienced a long lactational amenorrhoea had twice as much PRL, about half the total oestradiol, lower SHBG concentration (P < 0.05, Student's t-test, Bonferroni modification) and similar free oestradiol concentration, compared with those who experienced short lactational amenorrhoea. The difference in PRL concentration persisted in post-partum postsuckling samples.

CONCLUSIONS

At 38 weeks gestation, the ratio PRL/oestradiol identified all individual women according to the subsequent duration of their lactational amenorrhoea, suggesting that duration of lactational amenorrhoea is conditioned during pregnancy.

A practical approach for monitoring the reproductive cycle of primates is described. Ovulation, implantation, gestation and post-partum amenorrhoea were identified from measurements of total immunoreactive oestrogen and LH bioactivity in incomplete daily urine samples collected from various species, including a gorilla, a chimpanzee and an orang-utan. Oestrogen values were determined by radioimmunoassay of hydrolysed urine using a non-specific oestriol antiserum and LH was assessed by measuring testosterone output from dispersed rat Leydig cells. Both hormone measurements were indexed by urinary creatinine levels to help adjust for differences in urine concentration and volume.

We examined the changes in lipoprotein, apoprotein, and thrombophilia profile in postmenopausal women using a new cyclical sequential combined HRT regimen. The study medication consisted of two tablets of Hormonin (oestriol 0.27 mg, oestrone 1.4 mg and oestradiol 0.6 mg), daily and norethisterone (1 mg) BP (Shire Developments) for the last 12 days of every 28 day cycle. Serial fasting blood samples were collected at the beginning of the study and, thereafter, at 3-monthly intervals for 1 year, each patient acting as her own control. Thirty-five healthy postmenopausal women completed 1 year of follow-up and had a complete set of fasting blood samples. The lipid profile; total cholesterol, triglycerides, HDL, LDL, Apo AI, Apo AII, Apo B and Lp(a), as well as the coagulation parameters; antithrombin III, factor VII, fibrinogen, protein C and protein S, were measured at each occasion. There was a statistically significant drop in total cholesterol and LDL levels. Lp(a) level dropped after commencing treatment and remained below baseline for the rest of the study. The initial increase in Apo AII was not maintained for the duration of the treatment. The changes in Lp(a) and Apo AII were not statistically significant. The level of protein S dropped significantly throughout the study. The changes in other coagulation factors were not statistically significant. The effect of this hormonal combination on the lipid parameters is favourable, and although the change in protein S is striking, its clinical significance remains unclear.

The permeation across cellulose acetate of three oestrogens, differing only in the number of hydroxyl groups attached to the nucleus, and a 'standard' steroid, dexamethasone, was investigated using the lag-time method for calculating diffusion parameters, between 10 and 40 degrees. Diffusion coefficients for the similarly-sized oestrogens were relatively insensitive to marked changes in polarity, but increased permeation was correlated with increased partition coefficients, decreased polarity and fewer hydroxyl groups on the nucleus. Permeation increased with temperature and energies of activation were calculated from Arrhenius-type plots. Ep values ranged from 4-84 k cal mol-1 (20 kJ mol-1) for the least polar steroid (oestrone) to 6-91 k cal mol-1 (29 kJ mol-1) for the most polar steroid (oestriol). The results implied that steroid diffusion occurred through aqueous membrane channels, but that it was impeded to various extents by both obstruction and polar interaction effects.

Specific binding of [3H]oestradiol-17beta by the cytosol fraction of human renal cell carcinoma was studied. The binding reaction displayed marked ligand specificity and high affinity of binding. Unlabelled oestradiol, oestriol and oestrone inhibited the binding of [3H]oestradiol-17beta to the cytosol binding sites, wehereas all other steroids tested turned out to be only weak or insignificant competitors for the oestrogen binding sites. Scatchard analyses suggested the existence of a single class of binding sites. The dissociation constant of the oestradiol-binding complex was found to be 2.51 +/¿.75 x 10(-9) mol/l. The number of binding sites was limited (17.5 +/- 3.8 fmoles per mg of cytosol protein). Sucrose gradient centrifugation revealed these binding components to be macromolecules either displaying a complex sedimentation pattern (peaks at 3.5 S, 4S, 5.7S and, in addition, high molecular weight aggregates) or sedimenting in the 4S region alone. By agar gel electrophoresis it could be demonstrated that the oestradiol-inding components migrated into the receptor region of the gel. Binding of [3H]oestradiol-17beta to these entities was markedly reduced, when the cytosol was heated (60 min at 45 degrees C) prior to the reaction with the labelled hormone. Since the specific binding components exhibit properties of oestradiol receptors in target tissues, a direct effect of oestradiol on human renal cell carcinoma is suggested.

Urinary excretion of metabolites of the tryptophan-nicotinic acid ribonucleotide pathway, urinary excretion of 4-pyridoxic acid and blood concentrations of oestradiol and pyridoxal phosphate were studied in groups of post-menopausal women before or during treatment with natural oestrogens, i.e. oestradiol and oestriol, before and after loading doses of 9800 mumol L-tryptophan or 700 mumol L-kynurenine sulphate. Natural oestrogens induced abnormalities of tryptophan metabolism similar to those induced by synthetic oestrogens, and there was a dose related increase in urinary excretion of metabolites of the tryptophan-nicotinic acid ribonucleotide pathway before the kynureninase step. The increase in urinary excretion of these metabolites also after a loading dose of 700 mumol L-kynurenine indicates an inhibitory effect of oestrogens on kynureninase in vivo. Evidence is presented that this inhibition is an effect mediated through decreased availability of vitamin B6, the coenzyme of kynureninase, although the possibility of a direct effect of oestrogens on kynureninase can not be excluded.

Oestrogens, such as oestrone (E(1)), 17β-oestradiol (E(2)), oestriol (E(3)) and their biologically active metabolites 2-methoxyoestrone (2-MeOE(1)), 2-hydroxyoestradiol (2-OHE(2)) 16-ketooestradiol (16-OE(2)), 16-epioestriol (16-epiE(3)), as well as testosterone (T) play an important role in physiological and pathological developmental processes during human development. We therefore aimed at developing an isotope dilution/bench top gas chromatography-mass spectrometry (ID/GC-MS) method, based on benchtop GC-MS, for the simultaneous determination ('profiling') of the above analytes in children. The method consisted of equilibration of urine (5 ml) with a cocktail containing stable isotope-labelled analogues of the analytes as internal standards ([2,4-(2)H(2)]E(1), [2,4,16,16-(2)H(4)]E(2), [2,4,17-(2)H(3)]E(3), [16,16,17-(2)H(3)]T, [1,4,16,16-(2)H(4)]2-MeOE(1), [1,4,16,16,17-(2)H(5)]2-OHE(2), [2,4,15,15,17-(2)H(5)]16-OE(2) and [2,4-(2)H(2)]16-epiE(3)). Then, solid-phase extraction (C(18) cartridges), enzymatic hydrolysis (sulphatase from Helix pomatia (type H-1)), re-extraction, purification by anion exchange chromatography and derivatisation to trimethylsilyl ethers followed. The samples were analysed by GC-MS (Agilent GC 6890N/5975MSD; fused silica capillary column 25 m × 0.2 mm i.d., film 0.10 μm). Calibration plots were linear and showed excellent reproducibility with coefficients of determination (r(2)) between 0.999 and 1.000. Intra- and inter-assay coefficients of variation (CV) were <2.21% for all quantified metabolites. Sensitivity was highest for 2-OHE(2) (0.25 pg per absolute injection: signal-to-noise ratio (S/N)=3) and lowest for 16-epiE(3) (2 pg per absolute injection: S/N=2.6), translating into corresponding urine sample analyte concentrations of 0.025 ng ml(-1) and 0.2 ng ml(-1), respectively. Accuracy - determined in a two-level spike experiment - showed relative errors ranging between 0.15% for 16-OE(2) and 11.63% for 2-OHE(2). Chromatography showed clear peak shapes for the components analysed. In summary, we describe a practical, sensitive and specific ID/GC-MS assay capable of profiling the above-mentioned steroids in human urine from childhood onwards.

A cumulative sum technique has been specially designed to monitor the error between replicate determinations made on quality control plasma for consecutive batches of assays. This procedure has played a vital role in assessing assay performance. Special consideration has been given to small sample sizes (n = 2 or 3) which is generally the rule rather than the exception in many situations. This technique has been applied to numerous steroid radioimmunoassays and has ensured that both the mean value and the standard error of hormone levels of a quality control pool were under control. Data from routine assays of oestriol and testosterone in plasma from women are presented. Since this technique provides a sensitive measure of monitoring error, it assists the endocrinologist in elucidating statistical inferences which are a manifestation of assay performance.

Hyperglycosylated hCG is a form of hCG with more complex oligosaccharide side chains. A specific immunoassay was developed to measure hyperglycosylated hCG. Levels were measured in urine samples from 1157 women between 11 to 22 weeks of gestation, undergoing genetic analysis because of advanced maternal age. Values were normalized to urine creatinine concentration and plotted against gestational age, median values were determined and multiples of the control median (MoM) calculated. The median MoM and log standard deviation (log SD) of the 1134 control samples was 1.0 and 0.47, and of the 23 Down syndrome cases was 7.8 and 0.48, respectively. This indicated a 7.8-fold increase in hyperglycosylated hCG levels in Down syndrome cases. In the accompanying article, a stability problem was found with beta-core fragment measurements in frozen urine samples. In anticipation of similar problems, nine urine samples were tested for hyperglycosylated hCG fresh and after storage in the freezer. No clear difference was found in hyperglycosylated hCG values. In addition, no trend was found in hyperglycosylated hCG MoM values or in Down syndrome detection rates in urine samples stored for one, two or three years in the freezer. Samples were split into five equal groups according to creatinine concentration. A trend was observed, hyperglycosylated hCG MoM values decreasing with advancing creatinine concentration (1.77, 1.08, 1.01, 0.73 and 0.60 at 0.25, 0.50, 0.79, 1.11 and 1.73 mg/ml, respectively). An error was noted. This was corrected with a regression equation. After correction, the median MoM and log SD of the control samples was 1.0 and 0.44, and of Down syndrome samples was 7.3 and 0.42, respectively. Correction of this error, while reducing the elevation of Down syndrome cases, tightened the spread of samples. Samples were ranked and centiles determined. 18 of 23 Down syndrome cases (78 per cent) exceeded the 95th centile of the control population. ROC analysis indicated 79 per cent detection at 5 per cent false-positive rate. Urine samples were collected during two periods of gestation, an early period (11th to 14th completed week) and the period when chemical screening is normally performed (15th to 21st week). ROC analysis indicated 80 per cent and 78 per cent detection rates, respectively, at 5 per cent false-positive rate, in the two gestational periods. Hyperglycosylated hCG values were modelled with beta-core fragment values, total oestriol values and maternal age. ROC analysis indicated 97 per cent detection rate at 5 per cent false-positive rate. This detection rate and this level of Down syndrome and control patient discrimination surpasses that of any other serum, urine or ultrasound screening protocol. Hyperglycosylated hCG should be considered as a new screening test for aneuploid pregnancies, with the potential of detecting almost all cases of Down syndrome. Evaluation is needed by other centres in order to bring hyperglycosylated hCG into clinical practice.

Down's syndrome risks are estimated between 15 and 20 completed weeks' gestation (cGW) using an algorithm involving maternal age and serum alpha-fetoprotein (AFP), chorionic gonadotrophin and unconjugated oestriol levels, each expressed as a multiple of the median level (MoM) at the cGW. The AFP MoM itself is the basis for screening for open neural tube defects (oNTD). Because medians change during this period, gestational dating must be accurate so that appropriate medians are used. A calculated Down's syndrome risk>> 1:380 at term is generally considered to indicate a 'high-risk' pregnancy. This study focused on 378 patients with reported risk < or = 1:500 based on physician-supplied cGW (and hence considered at 'low risk' for Down's syndrome) to determine the effect of common 1-2-week dating errors on risk estimates. Using the original analytical data, each patient's risk was recalculated for each week over the 15-20 weeks, and classified into three categories: < 1:380 'low'; 1:380-1:100 'moderate'; and>> 1:100 'high'. Advancing originally 'low-risk' patients by one week increased the risk by 1.09-14.1 times (median 3.18, mean 3.60); 46 (12.2%) became 'moderate' and 2 (0.5%) became 'high' risk. Advancing by two weeks increased risks 1.58-60.5 times (median 10.03, mean 12.04); 131 (36.5%) became 'moderate' and 39 (10.9%) became 'high' risk. Predictably, oNTD screening results also were affected. Although 1-2 week differences in AFP medians had little effect on most patients in this study sample, some who originally were oNTD negative became oNTD positive, whereas others who had been oNTD positive became screen negative. Thus, in many cases, a 1-2 week dating error may have only minimal effect on the estimated risks for chromosome or neural tube defects, but in other cases the effect of such an error would be significant.

Pregnancy in a patient undergoing regular haemodialysis at home is described. The pregnancy was complicated by antepartum haemorrhage due to a Type I placenta praevia, and premature labour occurred at 32 weeks, resulting in spontaneous vaginal delivery of a live infant which survived. Plasma progesterone oestrone, unconjugated oestradiol and oestriol levels were normal during the last two weeks of pregnancy, but failed to show a characteristic fall in the puerperium. The conjugated oestriol fraction was 20 to 30 times the normal mean level and did not fall after delivery. These findings are discussed.

OBJECTIVE

To examine the fetal loss rate in women younger than 35 years of age following a false positive serum biochemical screening.

METHODS

Retrospective analysis of case records between 1991 and 1998.

METHODS

Fetal medicine unit of a large teaching hospital.

METHODS

Four hundred and fifty-six women with singleton pregnancies and false positive serum biochemical screening for Down's Syndrome (study group). Nine hundred and twelve matched controls with true negative serum biochemical screening (control group).

METHODS

Women of both groups had a second trimester serum screening for Down's Syndrome using alpha fetoprotein, human chorionic gonadotrophin (hCG) and unconjugated oestriol (uE3); and they also underwent genetic amniocentesis.

RESULTS

The overall fetal loss rate in the study group was 5.3% (24/456), compared with 1.65% (15/912) in the control group RR 3.2, 95% CI 1.7-5.99; P < 0.001). The majority of fetal losses in the study group occurred after 28 weeks, while in the controls this happened between 24 and 28 weeks of gestation.

CONCLUSIONS

A false positive serum biochemical screening in women under 35 years of age is associated with a threefold increased risk of subsequent fetal loss. However, most of fetal losses in this group occurred after 28 weeks, indicating that intensive antepartum fetal surveillance could improve the perinatal outcome.

Previous studies have shown that mid-trimester maternal serum alpha-fetoprotein (AFP) levels are significantly higher and human chorionic gonadotrophin (hCG) levels significantly lower in women with male compared with female fetuses. We have evaluated whether triple-screen criteria are more likely to identify women with female fetuses as at risk for Down syndrome. From the Georgetown University genetics database we obtained the absolute values and corresponding multiples of the median (MoM) for AFP, hCG and unconjugated oestriol (uE3) in singleton gestations for the period database November 1992 July 1996. A Down syndrome risk of 1/270 or greater at mid-trimester was considered as high risk. A total of 977 patients with triple screen and outcome information were identified, including 502 female and 475 male fetuses. Patients with female fetuses were significantly more likely to have lower serum AFP (p=0.003) and a positive triple screen for Down syndrome (72 (14 per cent) versus 45 (9 per cent), p<0.02) than those with male fetuses. The gestational age at triple screen, maternal serum hCG and uE3, race and diabetes were not significantly different between the two groups. Since Down syndrome is less common in female than male fetuses, and the rates of female and male Down syndrome fetuses detected by triple screen and subsequent amniocentesis are not significantly different, the excess of positive mid-trimester maternal serum triple screen in women with female fetuses is likely due to false-positive results.

Obstructive sleep apnoea (OSA) is prevalent in obese women with gestational diabetes mellitus (GDM). The present pilot study explored associations between OSA severity and metabolites in women with GDM. A total of 81 obese women with diet-controlled GDM had OSA assessment (median gestational age [GA] 29 weeks). The metabolic profile was assayed from fasting serum samples via liquid chromatography-mass spectrometry (LC-MS) using an untargeted approach. Metabolites were extracted and subjected to an Agilent 1,290 UPLC coupled to an Agilent 6,545 quadrupole time-of-flight (Q-TOF) MS. Data were acquired using electrospray ionisation in positive and negative ion modes. The raw LC-MS data were processed using the OpenMS toolkit to detect and quantify features, and these features were annotated using the Human Metabolite Database. The feature data were compared with OSA status, apnea-hypopnea index (AHI), body mass index (BMI) and GA using "limma" in R. Correlation analyses of the continuous covariates were performed using Kendall's Tau test. The p values were adjusted for multiple testing using the Benjamini-Hochberg false discovery rate correction. A total of 42 women (51.8%) had OSA, with a median AHI of 9.1 events/hr. There were no significant differences in metabolomics profiles between those with and without OSA. However, differential analyses modelling in GA and BMI found 12 features that significantly associated with the AHI. These features could be annotated to oestradiols, lysophospholipids, and fatty acids, with higher levels related to higher AHI. Metabolites including oestradiols and phospholipids may be involved in pathogenesis of OSA in pregnant women with GDM. A targeted approach may help elucidate our understanding of their role in OSA in this population.

Keywords: insulin resistance; intermittent hypoxia; lysophosphatidylcholine; oestriols; pre-eclampsia; sleep fragmentation.

To evaluate the relationship between serum hormone or aquaporin-2 (AQP-2) and preeclampsia, patients with severe preeclampsia (A group), mild preeclampsia (B group), chronic hypertension (C group) and normal pregnant women (D group) were recruited and analysed. The AQP-2 level in placenta tissues was detected and the correlations of AQP-2 with serum hormone levels were analysed using linear correlation regression analysis. The differences of alpha foetal protein (AFP) and human chorionic gonadotropin (HCG) levels during mid-pregnancy, as well as the levels of AFP, HCG, unconjugated oestriol and progesterone during late pregnancy were significant among A, B, C and D groups (p < .05). The AQP-2 level in placenta tissues was higher in A group than that in other groups (p < .05). The AQP-2 was correlated with HCG (p < .05). In conclusion, AQP-2 may be involved in the development of severe preeclampsia, which may be related to serum HCG.

This study was undertaken to evaluate the effects of oestriol in combination with oestradiol in the treatment of women with climacteric complaints. Forty-three post-menopausal women were randomly allocated to two groups on a double-blind basis. Over a 28-day cycle 23 of the women were treated sequentially for 12 days with 1 tablet containing 17 beta-oestradiol 2 mg plus oestriol 1 mg, then for 10 days with 1 tablet containing the same oestrogens plus norethisterone acetate 1 mg, thereafter for 6 days with 1 tablet containing 17 beta-oestradiol 1 mg plus oestriol 0.5 mg. The other 20 women received the same treatment but without the oestriol. No clinical, laboratory or histological differences were seen between the two groups. Both treatments were found to be equally effective in alleviating climacteric symptoms, with few side effects. It may be stated in conclusion that, on the basis of routine clinical and laboratory parameters no differences were found between the two preparations.

Comparative experimental study is performed on purification of yellow wastewaters separated and collected in solarCity, Linz, Austria. Three membrane methods (micro-, ultra-, and nano-filtration), and two advanced oxidations (gamma radiation and electrochemical oxidation) were applied. Best results concerning the removal of pharmaceuticals and hormones from urine by membrane separation were achieved using the membrane NF-200 (FilmTec). Pharmaceuticals (ibuprofen and diclofenac), and hormones (oestrone, beta-oestradiol, ethenyloestradiol, oestriol) were removed completely from urine. NF-separation also has some disadvantages: losses of urea, and lowering the conductivity in the product (permeate). The retentates (concentrates) received have to be treated further by oxidation to destroy the "problem" compounds. The results showed that electrochemical oxidation is more suitable than gamma radiation. Gamma-radiation with intensities higher than 10 kGy has to be applied for efficiently destroying of ibuprofen, and especially diclofenac. A high quantity of intermediate "problem" substances with oestrone structure was formed during the gamma oxidation of hormone containing urine samples. The electrochemical oxidation can be successfully applied for elimination of pharmaceuticals such as diclofenac, and hormones (oestrone, beta-oestradiol) from yellow wastewater without loss of urea (nitrogen fertiliser).

Background: Vulvodynia and pudendal neuralgia comprise significant contributors to vulvar-related pain and its impact on daily life.

Aim: A retrospective clinical audit was conducted at the Women's Health & Research Institute of Australia, Sydney, to determine the pattern of use and the efficacy of the application of topical amitriptyline 0.5% plus oestriol 0.03% in organogel (AOO), to the vulvar vestibule in reducing the impact of pain on daily life.

Materials and methods: There were 1174 patients who received a script from May 2017 until February 2020: 1054 patients agreed to be contacted and had a valid email address.

Results: There were 376 (35.7%) patients who replied. Pain with intercourse was the main indication for use. Treatment was rated effective by 51.2% (95% CI: 35.4-66.8%) of patients less than 30 years of age, 66.7% (95% CI: 57.3-74.9%) of patients 30-50 years of age, and 58.3% (95% CI: 50.9-65.4%) in patients over 50. Stinging at the site of application was the most commonly reported side effect.

Conclusion: Topical AOO is an effective and well-tolerated treatment for vulvar pain.

Keywords: dyspareunia; pelvic pain; pudendal neuralgia; vaginal mesh; vulvodynia.

The objective was to investigate whether non-immune hydrops in euploid pregnancies is associated with alterations in the second-trimester levels of maternal serum alpha-fetoprotein (AFP), unconjugated oestriol (uE3), and human chorionic gonadotropin (hCG). Ten singleton cases of fetal non-immune hydrops were identified. The aetiology and timing of onset of the earliest signs of non-immune hydrops, including polyhydramnios, in relation to maternal serum screening for Down syndrome were assessed. There was no clear relationship between the aetiology of non-immune hydrops and the analyte levels, as aetiologies varied widely. AFP levels were elevated overall (median = 1.78 MOM) and uE3 levels were unremarkable (median = 0.82 MOM). hCG levels were elevated (median = 3.53 MOM) when non-immune hydrops was present at the time of screening, but were unremarkable (median = 0.82 MOM) when the non-immune hydrops presented later. It is concluded that second-trimester non-immune hydrops is associated with elevated hCG levels.

Hydrops fetalis and fetal death caused by fetal parvovirus B19 infection have been reported to be associated with elevated maternal serum alpha-fetoprotein (AFP), based on a total of six cases. It has been suggested that the absence of AFP elevation may be reassuring. Maternal serum levels of the Down syndrome screening markers unconjugated oestriol and human chorionic gonadotropin in cases of fetal parvovirus infection have not been previously reported. We report four cases of hydrops fetalis and fetal death caused by fetal parvovirus infection, each with unremarkable second-trimester levels of AFP, unconjugated oestriol, and human chorionic gonadotropin.

The aim of the present study was to investigate the pharmacokinetics of oestriol in plasma in the dog after repeated oral administration of oestriol tablets, a preparation intended for the treatment of urinary incontinence in the bitch. The study was performed in six healthy, entire, adult female beagle dogs. The bitches were treated once daily with two tablets, containing 1 mg oestriol per tablet, for seven consecutive days (days 1-7). Blood samples were taken from the jugular vein before treatment, frequently on days 1, 3 and 7 of the treatment period and daily just before (C(trough)) and 1 h after dosing (C(t=1h)). During the washout period samples were taken at a 24 h interval up to four days post-treatment. Oestriol concentrations were determined in plasma by radioimmunoassay. Pharmacokinetic parameters, AUC, C(max) and t(max), were determined from the plasma concentration-time curves using non-compartmental methods. The between animal variation in C(max) and the AUC was high. Individual values of the C(max) varied from 206 pg/ml (day 1) to 1128 pg/ml (day 7) and the AUC(0-24h) from 789 pg x h/ml (day 1) to 5718 pg x h/ml (day 7). t(max) occurred within 1 h. The mean C(trough) value was slightly above the pre-treatment level ( 38+/-2 pg/ml vs. 18+/-5 pg/ml). Within 48 h after the last treatment the concentrations had returned to the pre-treatment values. C(max) and C(trough) did not increase during the treatment period, indicating that no accumulation occurred. A shoulder in the concentration-time curve around 8-12 h after treatment strongly suggested the existence of enterohepatic recirculation (EHR). The average relative contribution of the EHR to the AUC(0-24h) was estimated to be 22%, 38% and 44% on days 1, 3 and 7, respectively. These mean values were calculated from five animals per time point, because one dog failed to show EHR on days 1 and 3 and was therefore excluded from the calculations.