Hormone Monitoring Research Articles

Quantitative targeted GC-MS-based urinary steroid metabolome analysis for treatment monitoring of adolescents and young adults with autoimmune primary adrenal insufficiency

PurposePrimary adrenal insufficiency (PAI) is a rare and life-threatening disease. A recent Endocrine Society guideline argued against hormonal monitoring of glucocorticoid replacement. However, about 50% of adolescents and young adults (AYAs) with chronic diseases are non-adherent to their treatment regimens. Therefore, suitable hormonal monitoring of glucocorticoid replacement would be highly desirable in AYAs with PAI. We investigated whether quantitative targeted gas chromatography-mass spectrometry urinary steroid metabolome analysis would be suitable for monitoring glucocorticoid replacement in AYAs with autoimmune PAI. MethodRetrospective analysis of 21 urinary steroid profiles of four AYAs aged 15.6 ± 2.0 years with autoimmune PAI on hydrocortisone and fludrocortisone treatment. 24-hr cortisol metabolite excretion rates (CMERs) were calculated using the sum of major seven urinary cortisol metabolites. CMERs were transformed into z-scores according to reference values of healthy age- and sex matched subjects. ResultsThree patients showed good treatment adherence (17 of 21 samples). Mean CMER of these samples was 7.4 ± 1.8 mg/m2/d, corresponding to a z-score of 1.8 ± 1.1. CMER reflected 59.7 ± 14.5% of prescribed hydrocortisone dosages. A forth patient displayed clinical symptoms of PAI during treatment. CMER was only 0.3 mg/m2 (−3.4 z), reflecting only 3.1% of prescribed hydrocortisone dosage, compatible with lack of treatment adherence. Thereafter, the parents supervised the intake of tablets and treatment adherence improved. ConclusionQuantitative targeted GCMS steroid metabolome analysis could support monitoring of glucocorticoid replacement treatment in patients with PAI.

Levothyroxine versus Levothyroxine with Iodine in Reduction of Thyroid Nodule Volume: A Double-Blind Randomized Controlled Trial

Objective: To compare levothyroxine alone and in combination with iodine on thyroid nodule volume reduction.
 Methods: 
 Design: Double-Blind Randomized Controlled Trial
 Setting: Tertiary Government Hospital
 Participants: Nineteen (19) euthyroid patients age 19­-54 with at least 1 cytologically benign thyroid nodule were randomized to receive either levothyroxine + iodine or levothyroxine + placebo, taken once a day for 6 months with ultrasound and thyroid stimulating hormone monitoring on the 3rd and 6th month of intervention.
 Results: Main outcome measures included thyroid nodule volume reduction after six months of intervention. The mean change in volume from baseline to six months of levothyroxine + iodine group showed no statistically significant difference in nodule volume across time between levothyroxine + placebo group, -0.010 ± 1.250 (CI -0.521 - 0.501) versus 0.507 ± 1.128 (CI 0.025 - 0.990), p=.158. There were also new nodules (4 nodules) in the placebo group and none in the iodine group. No major adverse events were noted during the study.
 Conclusion: The two groups did not significantly differ in terms of nodule volume reduction.
 Keywords: thyroid nodule, prevention and control; drug therapy; iodine compounds, therapeutic use; levothyroxine, therapeutic use

Steroidomics for highlighting novel serum biomarkers of testosterone doping.

Aim: Quantification of testosterone (T) and 5α-dihydrotestosterone serum concentrations proved to be an efficient alternative to urinary steroid profiling for the detection of T doping. In this context, additional serum markers could be discovered by exploratory untargeted steroidomics studies. Results: Endogenous steroid metabolites were monitored by ultra high-performance liquid chromatography coupled to high-resolution mass spectrometry in serum samples collected during a T administration clinical trial. A three-step workflow for accurate review of annotation was used and multifactorial data analysis allowed highlighting promising serum biomarkers. Longitudinal monitoring of selected compounds was performed to assess T abuse detection capabilities. Conclusion: Application of serum steroidomics showed high potential for biomarker discovery of T doping, suggesting longitudinal monitoring of steroid hormones in serum as a significant improvement in detection of endogenous steroids abuse.

Clinical audit of immune related adverse events of the endocrine system with checkpoint inhibitor therapies - adopting a new algorithm for routine endocrine monitoring

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Vitamin D Does Not Affect Intraoperative Parathyroid Hormone Kinetics: A Mixed Linear Model Analysis

BackgroundIntraoperative parathyroid hormone (ioPTH) monitoring is used to confirm completeness of resection in patients undergoing parathyroidectomy for primary hyperparathyroidism (pHPT). Though there is an inverse relationship between vitamin D and parathyroid hormone (PTH), previous studies have suggested that 25-hydroxyvitamin D (25OHD) level does not affect the likelihood of meeting the Miami criterion. Here, we further investigate whether preoperative 25OHD level affects ioPTH kinetics. MethodsThis is a retrospective case-control study of patients undergoing parathyroidectomy for pHPT at a tertiary referral center. Patients were categorized based on preoperative 25OHD level as vitamin D deficient (≤ 20 ng/mL), insufficient (21-30 ng/mL), or sufficient (>30 ng/mL). Differences in baseline characteristics were analyzed with Kruskal-Wallis H test or chi-square analysis. ioPTH kinetic curves were analyzed using a log-transformed mixed linear model with subject-level random effects. Significance was set at P < 0.05. ResultsAmong 630 patients who met inclusion criteria, there was a significant difference in ioPTH between groups at baseline (P < 0.001), but not at any other time point. As a continuous variable, as well as a categorical variable, in a mixed linear model, vitamin D had no significant effect on ioPTH kinetics. ConclusionsDespite a difference in preoperative and baseline PTH levels, preoperative 25OHD had no significant effect on ioPTH kinetics. Therefore, ioPTH assays can be used and interpreted uniformly, regardless of patients’ vitamin D status.

Monitoring of behavior, sex hormones and boar taint compounds during the vaccination program for immunocastration in three sire lines

Immunocastration (vaccination against boar taint) is an alternative method to prevent boar taint without the need for surgical castration. This study investigates the evolution of boar taint compounds in serum and fat, serum steroid compounds as well as behavior in immunocastrated pigs from 3 sire lines: 15 stress positive Belgian Piétrain (BP), 20 stress negative French Piétrain (FP), and 20 stress negative Canadian Duroc (CD). Hormone and boar taint compounds in serum were determined at 4 time points; boar taint compounds in fat were determined at 3 time points. Behavior, skin lesions, animal and pen fouling were also recorded before the first vaccination (<V1), between the first and second vaccination (<V2), and after the second vaccination (>V2). Aggressiveness, eating and drinking and general activity behavior declined from <V1 to <V2 and > V2 for all sire lines. Pigs from BP were cleaner than FP and CD pigs. Even though immunocastration was effective in general (reduced testosterone, estradiol as well as androstenone in serum) for all sire lines, some individual pigs showed either androstenone or skatole levels in fat above cutoff values. While the immunocastration mechanism works as intended for androstenone, and also for skatole for the three sire lines, the risk of carcasses with boar taint compounds above cutoff levels (respectively 1.9 and 3.7%) still remains to some extent.

Intraoperative parathyroid hormone levels ≤40 pg/mL are associated with the lowest persistence rates after parathyroidectomy for primary hyperparathyroidism

BackgroundIntraoperative parathyroid hormone (IOPTH) monitoring is used to predict biochemical cure during parathyroidectomy for primary hyperparathyroidism; however, there is variability in the intraoperative parathyroid hormone criteria used by surgeons to predict normocalcemia after parathyroidectomy. This study sought to determine the intraoperative parathyroid hormone criteria correlated with the lowest rates of persistent hyperparathyroidism after parathyroidectomy for primary hyperparathyroidism. Materials and MethodsThis is a retrospective cohort study of 2,654 patients with primary hyperparathyroidism who underwent parathyroidectomy with intraoperative parathyroid hormone monitoring at a single institution from 1999 to 2014. Multivariate logistic regression analysis was used to measure the association between the lowest intraoperative parathyroid hormone level and the persistence of primary hyperparathyroidism after parathyroidectomy. ResultsA total of 66 patients (2.5%) had persistent hyperparathyroidism after parathyroidectomy. Using the traditional intraoperative parathyroid hormone criteria of a ≥50% decrease from the baseline level, the rate of persistent primary hyperparathyroidism was greater when intraoperative parathyroid hormone did not decrease to ≥50% from the baseline level (17 of 180 patients [9.4%] vs 49 of 2,474 [2.0%], [OR 5.9, 95% CI 3.2–10.5, P < .001]). Regardless of whether intraoperative parathyroid hormone decreased ≥50%, patients with a lowest intraoperative parathyroid hormone above the normal range (10–65 pg/mL) had greater persistence rates compared with patients with an intraoperative parathyroid hormone <65 pg/mL (30 of 350 [8.6%] vs 36 of 2,304 [1.6%], [OR 6.6, 95% CI 3.4–12.7, P < .001]). Furthermore, patients with a lowest intraoperative parathyroid hormone 40 to 65 pg/mL had increased rates of adjusted persistence compared with patients with lowest intraoperative parathyroid hormone ≤40 pg/mL (13 of 385 [3.4%] vs 23 of 1,919 [1.2%], [OR 4.2, 95% CI 2.0–8.7, P < .001]). Patients with lowest intraoperative parathyroid hormone <5 to 20 pg/mL did not have decreased rates of persistence compared with patients with lowest intraoperative parathyroid hormone 20 to 40 pg/mL (9 of 996 [0.9%] vs 14 of 923 [1.5%], [OR 0.5, 95% CI 0.2–1.2, P = .14]). ConclusionPatients with a lowest intraoperative parathyroid hormone ≤40 pg/mL compared with the traditional criteria of a ≥50% decrease from baseline and a final parathyroid hormone in the normal range (<65 pg/mL) had the lowest rates of persistent primary hyperparathyroidism after parathyroidectomy for primary hyperparathyroidism. The single criteria of a lowest intraoperative parathyroid hormone level ≤40 pg/mL may best predict the lowest persistent disease rates after parathyroidectomy for primary hyperparathyroidism.

Structural and functional features of endometrium in patients undergoing in - vitro fertilization

A complex of diagnostic and therapeutic measures had been established in order to overcome many different causes of female infertility and restore women’s reproductive health.The aim of research is to determine value of immunohistochemical method in determination of disregenerative condition of endometrium in patients undergoing in - vitro fertilization (IVF) program. Materials and methods. The research included 62 patients treated according to IVF program in Clinic of FSBI HPE KSMU NOH Russia, Krasnodar city, in 2017 year. Data of history of disease, laboratory diagnostics, hormonal monitoring at 2-3 day of menstrual cycle and dynamic ultrasound investigation were processed. To evaluate urogenital microbiocenosis real - time PCR was used with “Femoflor-16” kit. Pipelle - biopsy of endometrium was taken at 22-24 day of menstrual cycle. Results. After certain investigation patients were divided into three groups. First group consisted of 18 (29.03%) women with primary infertility, second group - 17 (27.42%) patients with secondary infertility, third group - 27 (43.55%) women with recurrent pregnancy loss. Absence of secretory transformation had been revealed in 27.7% women with primary infertility. In patients with secondary infertility and recurrent pregnancy loss proliferative disorders were less frequent, in11.8 and 7.4% respectively. Immunohistochemistry showed that recurrent pregnancy loss was not associated with impairment of both estrogen and progesterone receptors expression, unlike patients with primary and secondary infertility. In patients with recurrent pregnancy loss increased by 2.9 times collagen growth in endometrial stroma was detected. Conclusion. Addition of immunohistochemistry to routine histological investigation allows detection of impaired cyclic endometrial transformations during window of transformation which prevents successful implantation of blastocyst and pregnancy progression.

Detectability and surgical outcomes in parathyroid surgery – a single-centre experience

The incidence of primary hyperparathyroidismand referrals for the removal of parathyroid adenomas are increasing. Factors that improve the detectability, and ultimately the surgical outcome, are the focus of this retrospective study. We included 117 patients who had parathyroid operations with intraoperative monitoring of parathyroid hormone (PTH). Sestamibi, ultrasound and, in selected cases, fusion with computed tomograms (CT), were done to locate the lesion preoperatively. Concentrations of calcium and PTH before and after operation, specimen weight, and preoperative vitamin D concentrations, were assessed. The sensitivity of sestamibi and ultrasound for the preoperative location of adenomas was 92% and 80%, respectively. Sestamibi located them more accurately in patients with low preoperative concentrations of vitamin D (p = 0.037) and with heavier adenomas (p < 0.001). We found no significant association between the preoperative concentrations of PTH and detectability on preoperative scans (p = 0.058). Postoperative follow up showed that 97% of the 117 patients were biochemically cured. Accurate location helps to lower morbidity as it facilitates a targeted approach. Further studies are needed to explore the role of vitamin D in the location of parathyroid adenomas before parathyroidectomy.

Surgical management of pediatric thyroid disease: Complication rates after thyroidectomy at the Children's Hospital of Philadelphia high-volume Pediatric Thyroid Center

BackgroundRecent studies suggest improved outcomes for children undergoing thyroidectomy at high-volume pediatric surgery centers. We present outcomes after thyroid surgery at a single center and advocate for referral to high-volume centers for multidisciplinary management of these children. MethodsMedical records were reviewed for all pediatric patients undergoing thyroid surgery at a single institution from 2009 through 2017. Routine recurrent laryngeal nerve and parathyroid hormone monitoring was used. Lymph node dissections were performed in appropriately selected cancer patients. Data collection focused on pathologic diagnosis, surgical technique, and surgical complications, including postoperative hematoma, neurapraxia, permanent nerve damage, hypocalcemia, and transient and permanent hypoparathyroidism. ResultsFrom 2009 through 2017, 464 patients underwent thyroid surgery. Median age of the cohort was 15 years (range 2–24). Thirty-three percent were diagnosed with benign nodules (n=151), 36% with papillary or follicular thyroid cancer (n=168), 27% with Graves’ disease (n=124), 3% with medullary thyroid cancer (n=14), and 1.5% underwent prophylactic thyroidectomy for MEN2a (n=7). Six patients required return to the OR for hematoma evacuation including 5 patients after surgery for Graves’ disease (RR 8.7, 95% CI 1.06–71.85). In sixteen cases, concern about neurapraxia resulted in laryngoscopy, revealing eleven patients with vocal cord paresis. Two of these patients demonstrated a persistent deficit at 6 months postoperatively (0.4%). Thirty-seven percent of patients had transient hypoparathyroidism (n=137), and two patients had persistent hypoparathyroidism 6 months after total thyroidectomy (0.6%). There was no significant difference in either hypocalcemia or hypoparathyroidism after total thyroidectomy based on age or diagnosis. ConclusionsCharacterizing outcomes for pediatric patients based on diagnosis will assist in preoperative counseling for patients and their families. This high-volume center reports low complication rates after pediatric thyroid surgery, highlighting that referral to high-volume centers should be considered for children and adolescents with thyroid disease requiring surgery. Level of evidenceLevel IV

Measuring luteinising hormone pulsatility with a robotic aptamer-enabled electrochemical reader

Normal reproductive functioning is critically dependent on pulsatile secretion of luteinising hormone (LH). Assessment of LH pulsatility is important for the clinical diagnosis of reproductive disorders, but current methods are hampered by frequent blood sampling coupled to expensive serial immunochemical analysis. Here, we report the development and application of a Robotic APTamer-enabled Electrochemical Reader (RAPTER) electrochemical analysis system to determine LH pulsatility. Through selective evolution of ligands by exponential enrichment (SELEX), we identify DNA aptamers that bind specifically to LH and not to related hormones. The aptamers are integrated into electrochemical aptamer-based (E-AB) sensors on a robotic platform. E-AB enables rapid, sensitive and repeatable determination of LH concentration profiles. Bayesian Spectrum Analysis is applied to determine LH pulsatility in three distinct patient cohorts. This technology has the potential to transform the clinical care of patients with reproductive disorders and could be developed to allow real-time in vivo hormone monitoring.

Feeling like a winner: Affective state, emotional state, and hormone monitoring in division I athletes

Pulsatile ultradian secretion of cortisol, rarely studied in salivary data, has functional importance in hypothalamic pituitary adrenal (HPA) axis regulation. The first daily ultradian episode, the cortisol awakening response (CAR), was examined in healthy adults, in 5-min secretion rates of salivary cortisol from electronically monitored awakening time to 1.25 h. Aggregated rates revealed a cubic trend, with wave-length of almost exactly 1 h, as predicted from known ultradian periodicity. Peak secretion rate occurred 20-min post-awakening. Peak (20-min) to trough (59-min) amplitude (PTA) expressed a salient signal shape. Rates rose steeply to and from peak, and major secretion was packaged into a few 5-min intervals, inconsistent with normal or uniform distribution of 5-min rates, but consistent with known pulsatile cortisol delivery. Null hypotheses asserting normal or uniform distributions were rejected. Maximal rates overwhelmingly occurred before and minimal rates after 30-mins, with degree of extremity at each polarity significantly positively correlated.To demonstrate utility and reliability of PTA estimation in a clinically relevant domain, re- analyses of a previously published study were conducted. Data from only three saliva samples were used, given importance of cost considerations for many CAR researchers. Difference between mean rates before and after 30-min yielded a simple salience index, highly correlated with PTA derived from full 5-min interval data. CAR salience performed significantly better than traditional AUCi magnitude in discriminating control cases (higher inferred amplitude) and cases with Seasonal Affective Disorder (lower inferred amplitude). Evidence suggested that low AUCi may be more sensitive in identifying within-subject changes (e.g. more depressed mood in winter among SAD cases) and low CAR salience better at revealing enduring between-subjects associations (e.g. underlying disorder vulnerability). Since both PTA salience and AUCi magnitude can be analysed and compared using exactly the same data from the same commonly used saliva sampling points, further research is warranted into the importance of individual differences in patterns of cortisol delivery, not just how much is delivered.

Primary Hyperparathyroidism

Primary hyperparathyroidism is defined. Key components of the diagnostic work-up including symptoms, family history, laboratory examination, and imaging techniques are reviewed. Indications for surgery, including a discussion of the latest guidelines, are emphasized. Controversies such as when to operate on asymptomatic primary hyperparathyroidism are discussed. This review contains 4 figures, 1 table, and 29 references. Key Words: hypercalcemia, hypercalcemic crisis, intraoperative parathyroid hormone monitoring, multiple endocrine neoplasia, normocalcemic primary hyperparathyroidism, parathyroid adenoma, parathyroid hyperplasia, primary hyperparathyroidism, sestamibi scan

Primary Hyperparathyroidism

Primary hyperparathyroidism is defined. Key components of the diagnostic work-up including symptoms, family history, laboratory examination, and imaging techniques are reviewed. Indications for surgery, including a discussion of the latest guidelines, are emphasized. Controversies such as when to operate on asymptomatic primary hyperparathyroidism are discussed. This review contains 4 figures, 1 table, and 29 references. Key Words: hypercalcemia, hypercalcemic crisis, intraoperative parathyroid hormone monitoring, multiple endocrine neoplasia, normocalcemic primary hyperparathyroidism, parathyroid adenoma, parathyroid hyperplasia, primary hyperparathyroidism, sestamibi scan

Operative Approach to Primary Hyperparathyroidism

We review the key components of the embryology and anatomy of the parathyroid glands. Here, minimally invasive parathyroidectomy with intraoperative adjuncts such as intraoperative parathyroid hormone monitoring, four-gland exploration, subtotal parathyroidectomy, total parathyroidectomy with autotransplantation, and cyropreservation are described. The incidence of postoperative complications and the technical aspects of parathyroid surgery are delineated. This review contains 3 figures, 1 tables, and 17 references. Key Words: cryopreservation, hyperparathyroidism, minimally invasive parathyroidectomy parathyroidectomy, pharyngeal pouch, recurrent laryngeal nerve, subtotal parathyroidectomy, total parathyroidectomy

Operative Approach to Primary Hyperparathyroidism

We review the key components of the embryology and anatomy of the parathyroid glands. Here, minimally invasive parathyroidectomy with intraoperative adjuncts such as intraoperative parathyroid hormone monitoring, four-gland exploration, subtotal parathyroidectomy, total parathyroidectomy with autotransplantation, and cyropreservation are described. The incidence of postoperative complications and the technical aspects of parathyroid surgery are delineated. This review contains 3 figures, 1 tables, and 17 references. Key Words: cryopreservation, hyperparathyroidism, minimally invasive parathyroidectomy parathyroidectomy, pharyngeal pouch, recurrent laryngeal nerve, subtotal parathyroidectomy, total parathyroidectomy

MONITORING OF PROGESTERONE AND ESTRONE FECAL METABOLITES THROUGHOUT GESTATION IN EWES

Abstract The aim of this study was to monitor the progesterone and fecal estrone metabolites throughout gestation in ewes correlating with the serum levels of these steroid hormones. Therefore, fecal and serum samples were collected from 5 weeks before mating and gestation until two weeks postparturition. Serum levels of progesterone and estrone and their fecal metabolites were measured by enzyme immunoassay. Serum and fecal hormonal patterns showed a significant correlation for both hormones (R = 0.8572, P &lt; 0.001 for progesterone and R = 0.5893, P &lt; 0.001 for estrone). The fecal progesterone metabolite levels showed significant increasing values among the three thirds of pregnancies, consistent with the serum levels and with the literature. Additionally, the prepartum peak of estrone in the fecal matrix was identified but without observation in the serum matrix due to the blood collection interval used. Therefore, this study demonstrated the viability of progesterone and estrone monitoring throughout gestation using fecal samples, making noninvasive longitudinal endocrine monitoring throughout gestation possible in this species.

Prenatal Diagnosis of Fetal Goiter: Case Report and Review of Literature

Pregnancy hyperthyroidism due to Plummer’s disease is an uncommon event. Therapy is based on propylthiouracil (PTU), starting from the first trimester of pregnancy. Among the complications of the antithyroid drugs (ATDs) there is the risk of hypothyroidism and fetal goiter, in addition to well - known possible teratogen effects. Maternal hormonal monitoring with a personal ized pharmacological treatment and fetal ultrasound control, starting from the 18 th week of pregnancy, are mandatory for the mother and fetus’ health and therefore for a successful pregnancy. In this paper we’ll describe the case of a woman with toxic aden oma, in which the ultrasounds diagnosis of fetal goiter at the 29 th gestational - week of pregnancy and the consequent suspension of the ongoing therapy with PTU, succeeded in the end of the pregnancy with the birth of a healthy fetus.

Intraoperative Parathyroid Hormone Monitoring in the Surgical Management of Sporadic Primary Hyperparathyroidism.

Intraoperative parathyroid hormone monitoring (IPM) has been shown to be a useful adjunct during parathyroidectomy to ensure operative success at many specialized medical centers worldwide. Using the Miami or “>50% intraoperative PTH drop” criterion, IPM confirms the complete excision of all hyperfunctioning parathyroid tissue before the operation is finished, and helps guide the surgeon to identify additional hyperfunctioning parathyroid glands that may necessitate further extensive neck exploration when intraoperative parathyroid hormone (PTH) levels do not drop sufficiently. The intraoperative PTH assay is also used to differentiate parathyroid from non-parathyroid tissues during operations using fine needle aspiration samples and to lateralize the side of the neck harboring the hypersecreting parathyroid through differential jugular venous sampling when preoperative localization studies are negative or equivocal. The use of IPM underscores the recognition and understanding of sporadic primary hyperparathyroidism (SPHPT) as a disease of function rather than form, where the surgeon is better equipped to treat such patients with quantitative instead of qualitative information for durable long-term operative success. There has been a significant paradigm shift over the last 2 decades from conventional to focused parathyroidectomy guided by IPM. This approach has proven to be a safe and rapid operation requiring minimal dissection performed in an ambulatory setting for the treatment of SPHPT.

Evaluation of respiratory vapour and blubber samples for use in endocrine assessments of bottlenose dolphins (Tursiops spp.)

Blubber and respiratory vapour (‘blow’) are now commonly used for endocrine studies on cetaceans, primarily because they can be obtained using minimally invasive methods. For many species, these samples have yet to be validated for these purposes. The objective of this study was to examine the performance of blow and blubber hormone monitoring, relative to serum hormone monitoring, for evaluating the reproductive and adrenal condition of captive bottlenose dolphins (Tursiops spp.). Eighteen bottlenose dolphins were sampled five times for serum and blow and twice for blubber throughout a one-year period. Concentrations of progesterone, testosterone, oestradiol and cortisol were measured in each sample type. Hormone levels were examined in relation to dolphin age, sex, reproductive status, season, time of sample collection (morning/afternoon) and collection type (in- or out-of-water sampling). Patterns in hormone levels were similar for serum and blubber. For instance, in both sample types, progesterone levels were significantly higher in pregnant (serum: 34.10 ± 8.64 ng/mL; blubber: 13.01 ± 0.72 ng/g) than in non-pregnant females (serum: 0.32 ± 0.09 ng/mL; blubber: 1.17 ± 0.10 ng/g). This pattern was not detected in blow, primarily because seawater contamination, nylon sampling materials and variable sample volumes influenced measured concentrations. In addition, the respiratory water content of a blow sample is known to affect measured hormone levels. Two methods were trialled to control for variability in sample volumes and dilution: (1) normalising blow hormone concentrations relative to urea nitrogen levels (a potential endogenous standard), and (2) measuring the relative proportions (i.e. ratios) of blow hormones. These correction measures had little influence on blow hormone results. Further refinement of blow hormone monitoring methods is required before they can be used for reproductive or adrenal assessments of bottlenose dolphins. Blubber, on the other hand, should be a suitable proxy for serum when attempting to classify pregnancy status and male maturity in these species.