Corticosteroid-binding Globulin Research Articles

A proteome perspective on adaptive responses to physiological challenges in marine mammals

While most mammals decrease energy expenditure while fasting, marine mammals such as northern elephant seals fast for several months while undergoing energy-intensive life history stages (e.g., postnatal development, molting, reproduction). Energy for these functions is provided by mobilization of large energy stores in blubber, which is driven by elevation of stress hormone levels across the fast. We used a proteome approach to examine potential mechanisms regulating fasting metabolism and responses to experimental stress challenges in elephant seals. We compared five proteome datasets and identified proteins that were altered by both fasting and experimental stress challenges across multiple life history stages and tissues in seals. These included lipid and hormone transport proteins (e.g., apolipoproteins, corticosteroid-binding globulin, transthyretin), acute phase proteins (e.g., alpha-2-macroglobulin, haptoglobin), antioxidant enzymes (e.g., glutathione peroxidase 3, catalase), adipokines (e.g., mimecan), and metabolic enzymes (e.g., fatty acid synthase, long chain fatty acid CoA ligase), among others. We suggest that these proteins may function as part of a core adaptive responses to physiological challenges in marine mammals. However, our ability to identify components of these responses has been hindered by several practical and technical challenges, and we will discuss the limitations and considerations for using a proteome approach in comparative physiology studies based on our experience. This research was funded by University of the Pacific and Offce of Naval Research. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Comparative analysis of salivary cortisol measurements using different assay methods in relation to serum-free cortisol measurement

ObjectivesSalivary cortisol reflects the biologically active form of serum cortisol, offering a noninvasive evaluation method for the diurnal rhythm of the hypothalamic-pituitary-adrenal (HPA) axis. While liquid chromatography-tandem mass spectrometry (LC-MS/MS) is known for its specificity, immunoassays (IA) are commonly used because of their simplicity. This study aimed to assess the performance of salivary cortisol measurement using both IA and LC-MS/MS in comparison to serum-free cortisol measurement. MethodsAssay results for 188 saliva and 94 serum samples from 47 participants were analyzed. Salivary samples collected at different time points were analyzed using IA and LC-MS/MS. Serum samples were analyzed for cortisol, cortisol-binding globulin, and free cortisol. The statistical analyses included correlations and method comparisons. ResultsThe diurnal salivary cortisol profiles exhibited a comparable circadian rhythm pattern; however, the concentrations measured using IA were consistently higher than those measured using LC-MS/MS. The correlation analysis revealed robust associations among salivary cortisol (IA), salivary cortisol (LC-MS/MS), and serum-free cortisol levels (LC-MS/MS). However, the method comparison revealed a systematic bias between IA and LC-MS/MS in salivary cortisol measurement. ConclusionsThis study contributes to the ongoing debate on assay techniques by affirming the suitability of IA and LC-MS/MS for salivary cortisol measurement to assess dynamic changes in HPA axis activity. The identified systematic bias emphasizes the importance of selecting methods based on specific research or clinical requirements.

Fabrication of an affordable and sensitive corticosteroid-binding globulin immunosensor based on electrodeposited gold nanoparticles modified glassy carbon electrode

Herein, we fabricated an ultrasensitive electrochemical immunosensor for the quantitative detection of corticosteroid-binding globulin (CBG). CBG is a protein that regulates glucocorticoid levels and is an important biomarker for inflammation. A decrease in CBG levels is a key biomarker for inflammatory diseases, such as septic shock. To enhance the electrochemical performance and provide a large surface area for anti-CBG immobilization, we functionalized the glassy carbon electrode surface with AuNPs. Electrochemical characterization methods including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to examine the construction of the fabricated immunosensor. The electrochemical signal demonstrated a remarkable sensitivity to the CBG antigen, with a detection range from 0.01 to 100 μg/mL and a limit of detection of 0.012 μg/mL, making it suitable for both clinical and research applications. This label-free immunosensor offers significant advantages, including high sensitivity, low detection limits and excellent selectivity, making it a promising tool for detecting CBG in complex biological samples. Its potential applications include early disease diagnosis, treatment monitoring and studying CBG-related physiological processes.

Long-acting porcine ACTH stimulated salivary cortisol reduces the overdiagnosis of adrenal insufficiency compared to serum cortisol in cirrhosis liver.

There are no reliable methods in clinical practice to diagnose adrenal insufficiency (AI) in patients with cirrhosis owing to variable cortisol-binding protein levels. This leads to unreliable results in ACTH stimulated serum cortisol test. We aimed to estimate the long-acting porcine (LA)ACTH-stimulated serum and salivary cortisol levels of patients at different stages of cirrhosis using second generation electrochemiluminescence and to determine the prevalence of true adrenal insufficiency in these patients. We included 135 noncritical patients with cirrhosis (45 each from CHILD A, Band C) and 45 healthy controls. Serum and salivary samples were collected at baseline in the morning and at 1and 2 h after LA-ACTH injection. In healthy subjects, the 2.5th centile of 2 h ACTH stimulated serum and salivary cortisol were 19.8and 0.97 μg/dL, which were used as cut-offs for defining AI based on serum and saliva respectively. The median (interquartile-range) 2-h stimulated salivary cortisol in Child A, B, C categories and controls were 1.36(1.23-2.38), 1.46(1.18-2.22), 1.72(1.2-2.2) and 2.12(1.42-2.72) μg/dLrespectively. Six subjects (4.4%) were diagnosed to have AI based on stimulated salivary cortisol cut-off, whereas 39 (28.9%) cirrhosis subjects had inadequately stimulated serum cortisol. Three patients (symptomatic) required steroid replacement therapy. Hypoalbuminemia was identified as a major risk factor for the misdiagnosis of adrenal insufficiency by serum cortisol-based testing. Long-acting porcine ACTH stimulated salivary cortisol reduces the overdiagnosis of adrenal insufficiency compared to serum cortisol in cirrhosis liver. Stimulated salivary cortisol is a promising investigation for evaluation of adrenal function in cirrhosis and more studies are required for its further validation before clinical use.

The intrafollicular concentrations of biologically active cortisol in women rise abruptly shortly before ovulation and follicular rupture.

What is the temporal activity and the concentration in follicular fluid (FF) of the anti-inflammatory steroid cortisol during the ovulatory process in humans? Intrafollicular concentrations of cortisol become massively upregulated close to ovulation concomitant with an exceptionally high biological activity securing a timely and efficient termination of inflammatory processes. Ovulation has been described as a local, controlled inflammatory process resulting in the degeneration of the follicle wall which facilitate oocyte extrusion. Ovulation also affects the glucocorticoid metabolism of granulosa cells (GCs) and although de novo synthesis of cortisol only occurs in the adrenal cortex, the mid-cycle surge has been shown to induce a change from high expression of HSD11B2, inactivating cortisol to cortisone, to high expression of HSD11B1 which reversibly catalyses cortisol production from cortisone. Furthermore, high concentrations of progesterone and 17OH-progesterone within follicles may cause dislodging of cortisol from cortisol binding protein (CBP) thereby activating the biological activity of cortisol. This prospective cohort study included 50 women undergoing fertility treatment according to a standard antagonist protocol at a university hospital-affiliated fertility clinic in Denmark. Women donated FF and GCs from one follicle for research purpose aspirated at one of four time points during the process of final maturation of follicles: T = 0 h, T = 12 h, T = 17 h, T = 32 h. A second sample was collected at oocyte pick up at T = 36 h. The concentration of cortisol and cortisone together with a range of sex steroids was measured by LC-MS/MS in FF collected at the five time points mentioned above. Whole genome microarray data, validated by q-PCR analysis, was used to evaluate gene expression of CYP11B1, CYP21A2, HSD11B1, HSD11B2, and NR3C1 in GCs at the same time points. The concentration of cortisol was significantly increased from a few nM at 0 h to around 100-140 nM (P ≤ 0.0001) at 32-36 h, whilst cortisone was almost constant from 0 to 17 h at a concentration of between 90 and 100 nM being significantly reduced to 25-40 nM (P ≤ 0.0001) at 32-36 h. This was paralleled by a 690-fold upregulation of HSD11B1 from 0 to 12 h increasing to a more than 20.000-fold change at 36 h. HSD11B2 was quickly downregulated 15- to 20-fold after ovulation induction. Concentrations of progesterone and 17OH-progesterone increased during the ovulatory process to high levels which in essence displaces cortisol from its binding protein CBP due to similar binding affinities. Furthermore, a significant decrease in 11-deoxycortisol expression was seen, but CYP11B1 expression was below detection limit in GCs. The study included women undergoing ovarian stimulation and results may differ from the natural cycle. More observations at each specific time point may have strengthened the conclusions. Furthermore, we have not been able to measure the actual active biological concentration of cortisol. For the first time, this study collectively evaluated the temporal pattern of cortisol and cortisone concentrations during human ovulation, rendering a physiological framework for understanding potential dysregulations in the inflammatory reaction of ovulation. This research was supported by the University Hospital of Copenhagen, Rigshospitalet, and Novo Nordisk Foundation grant number NNF21OC00700556. Interreg V ÔKS through ReproUnion (www.reprounion.eu); Region Zealand Research Foundation. The funders had no role in study design, collection of data, analyses, writing of the article, or the decision to submit it for publication. The authors have no conflicts of interest to declare. N/A.

The impact of mitotane therapy on serum-free proteins in patients with adrenocortical carcinoma.

Adrenocortical carcinoma (ACC) is a rare malignancy of the adrenal cortex. Whilst surgery is the preferred treatment, adjunctive therapy with mitotane may be offered post-surgically to minimise the risk of recurrence or, in the absence of surgery, to attenuate progression. The objective was to evaluate the effects of mitotane treatment on serum protein concentrations in patients treated for ACC with mitotane therapy and compare this to patients with other adrenal neoplasms and a normal pregnant cohort. Serum cortisol, thyroid function tests, adrenocorticotrophic hormone (ACTH), cortisol-binding globulin (CBG), thyroxine-binding globulin (TBG), gonadotrophins and androgens were measured on plasma and serum samples. Thirty-five patients with ACC were included, and mitotane levels were noted to be sub-/supra-therapeutic. Data were tested for normality, reported as mean ± s.d., and compared to other two cohorts using paired-sample t-test with a 5% P-value for significance and a 95% CI. Patients on mitotane therapy had a higher mean serum CBG concentration compared to the adrenal neoplasm group (sub-therapeutic: 79.5 (95% CI: 33.6, 125.4 nmol/L), therapeutic: 85.3 (95% CI: 37.1-133.6 nmol/L), supra-therapeutic: 75.7 (95% CI: -19.3, 170.6 nmol/L) and adrenal neoplasm: 25.5 (95% CI: 17.5, 33.5 nmol/L). Negative correlations between serum cortisol and CBG concentration were demonstrated within the supra-therapeutic plasma mitotane and adrenal neoplasm groups. Patients with ACC and therapeutic plasma mitotane concentrations had higher serum CBG concentrations compared to those with adrenal neoplasms or pregnant women, and higher serum cortisol. Whilst there was no direct correlation with cortisol and mitotane level, the negative correlation of cortisol with CBG may suggest that the direct effect of mitotane in increasing cortisol may also reflect that mitotane has a direct adrenolytic effect.

O-03 Adrenalectomy for Cushing's syndrome during pregnancy

Abstract Introduction Cushing's syndrome (CS) is rare in pregnancy because CS itself is a cause of anovulatory infertility due to excess cortisol secretion. Moreover it is also difficult to diagnose CS in pregnancy because placental production of corticotropin releasing and adrenocorticotropic hormone (ACTH), increased maternal production of estrogen induced corticosteroid binding globulin leads to physiological hypercortisolism during pregnancy. So physicians face a clinical overlap in many features of CS such as weight gain, fatigue, edema, hypertension, hyperglycemia, stretch marks, mood changes that can also be attributed to pregnancy. Thus their coexistence represents a diagnostic challenge. Herein we report a case of CS that was diagnosed and successfully treated during pregnancy. Clinical Case A 43-year-old gravida 3 female was consulted at the 21st week of gestation with persistent high blood pressure and hyperglycemia for a month. She had an obstetric history of 2 spontaneous first term abortion, 2 healthy labor 18 years ago and she was healthy after. She was in such a depressive mood that she was consulted with psychiatry many times. On physical examination edema, proximal weakness of lower extremities and hirsutism (modified Ferriman–Gallwey score of 9) was detected. Initial laboratory tests were all within normal range except potassium level (2.7 mmol/L), the results were not consistent with preeclampsia and there was a suspicious adrenal mass detected on ultrasound. She was currently receiving high dose antihypertensive treatment with methyldopa, calcium channel blockers, rapid acting and detemir insulin for diabetes and i.v. potassium replacement. We ruled out conns syndrome with normal plasma aldosterone renin ratio and found catecholamine levels normal. Hormonal analyses revealed with high plasma cortisol levels, increased nocturnal cortisolemia, a suppressed plasma ACTH and dehydroepiandrosterone sulfate level and distinctly elevated 24-hour urinary cortisol greater than 3-fold the upper normal reference range. Non contrast magnetic resonance imaging demonstrated a 47×32 mm left adrenal mass. Laparoscopic adrenalectomy was performed in the 26th week of gestation and the following histopathology revealed an adrenocortical adenoma. Antihypertensive medication was progressively reduced, glycemic control and hypokalemia reversal were achieved. She was followed up with appropriate glucocorticoid replacement. At 34 weeks of gestation, after sudden labor pain and regular uterine contractions a 2586 g male infant with Apgar scores of 8 was born by cesarean section. They were discharged in good health. Conclusion CS should be kept in mind especially in the case of hypertension and diabetes that started before the 20th gestational age. Analysis of the urinary free cortisol level and circadian rhythm of cortisol is necessary to diagnose. Despite the diagnostic challenge we can achieve better maternal and fetal outcomes with proper management.Figure 1.Non-contrast magnetic resonance imaging of the patient Table 1.Patient's laboratuary test results Table 2.Patient's laboratory test results

Salivary Cortisol and Cortisone Can Circumvent Confounding Effects of Oral Contraceptives in the Short Synacthen Test.

Adrenal insufficiency (AI) is usually diagnosed by low plasma cortisol levels following a short Synacthen test (SST). Most plasma cortisol is bound to corticosteroid-binding globulin, which is increased by estrogen in combined estrogen-progestin oral contraceptives (COCs). Women with AI using COCs are therefore at risk of having an apparently normal plasma cortisol level during SST, which would not adequately reflect AI. To test whether salivary cortisol or cortisone during SST is more robust against the COC effect and to calculate the lower reference limits (LRLs) for these to be used as tentative diagnostic cutoffs to exclude AI. Forty-one healthy women on COCs and 46 healthy women without exogenous estrogens performed an SST with collection of plasma and salivary samples at 0, 30, and 60 min after Synacthen injection. The groups were compared using regression analysis with age as covariate and the LRLs were calculated parametrically. SST-stimulated plasma cortisol levels were significantly higher in the COC group versus controls, while mean salivary cortisol and cortisone levels were slightly lower in the COC group. Importantly, COC use did not significantly alter LRLs for salivary cortisol or cortisone. The smallest LRL difference between groups was seen for salivary cortisone. Salivary cortisol and especially salivary cortisone are considerably less affected by COC use than plasma cortisol during SST. Due to similar LRLs, a common cutoff for salivary cortisol and cortisone during SST can be used to exclude AI in premenopausal women irrespective of COC use.

ЗНАЧЕНИЕ СВЯЗЫВАНИЯ КОРТИКОСТЕРОИДОВ С БЕЛКАМИ ПЛАЗМЫ КРОВИ В МЕХАНИЗМЕ ВЛИЯНИЯ РАДИОПРОТЕКТОРА РС-11 НА ФУНКЦИЮ КОРЫ НАДПОЧЕЧНИКОВ ПРИ ОСТРОЙ ЛУЧЕВОЙ БОЛЕЗНИ

Purpose: To study the role of binding of corticosteroids to blood plasma proteins in the mechanism of influence of the radioprotector RS-11 on the function of the adrenal cortex in irradiated animals. Material and methods: The experiments were carried out on 30 male chinchilla rabbits weighing 2.5–3.0 kg. The first series of experiments is aimed at studying the reaction of the adrenal cortex and the processes of protein-steroid interaction after the administration of PC-11 to intact animals; in the second series – the same indicators in animals irradiated during the prophylactic administration of RS-11. The total content of 11-hydroxycorticosteroids (11-OKS) in blood plasma was determined by the fluorometric method of Guillemin et al in the author’s modification. The amount of free corticosteroids was determined by the difference in their content in whole plasma and in its protein fraction after separation on Sephadex G-25. Binding capacity of corticosteroid binding globulin (CSBG) was determined by gel filtration De Moor at al. in the author’s modification. Statistical analysis of the study results was carried out using the Student–Fisher method. Results: In the group of intact rabbits under conditions of administration of PC-11, the reaction of the adrenal cortex after 2.5–3 hours was significantly higher compared to control animals. The increase in the free fraction of the hormone with the introduction of the radioprotector RS-11 during this period is associated with an increase in the total level of 11-OKS, since the binding ability of CSBG did not change. In the group of irradiated rabbits, 2.5–3 hours after irradiation, the administration of PC-11 also led to a significant increase in the total content of 11-OKS in the blood compared to the initial data. At the height of radiation sickness on the 4th day, RS-11 protected rabbits showed a significantly smaller decrease in the binding capacity of CSBG than control animals, and the total content of 11-OKS was higher than in the control. The level of free hormone on the 4th day was sharply reduced (8 % of the total 11-OKS content versus 41 % in the control). On the 8th day of radiation sickness, free 11-OKS in protected RS-11 and control rabbits was practically absent, however, in protected animals, the binding capacity of CSBG was 2 times higher than in control animals. Conclusions: The influence of the radioprotector RS-11 leads in the first hours to an increase in the total concentration of 11-OX in the blood plasma and to an increase in the amount of free hormone in intact animals. The binding capacity does not change. Prophylactic administration of RS-11 inhibits, at the height of radiation sickness, the decrease in the binding capacity of CSBG in the blood plasma, and as a result, the increase in the level of free physiologically active hormone at a higher overall level of hormones in the blood. In the mechanism for reducing post-radiation hypercortisolism under conditions of protection with the drug RS-11, the main significance is the lesser degree of disruption of the binding ability of CSBG, and not a change in the overall level of hormones in the blood.

Position-specific N- and O-glycosylation of the reactive center loop impacts neutrophil elastase–mediated proteolysis of corticosteroid-binding globulin

Corticosteroid-binding globulin (CBG) delivers anti-inflammatory cortisol to inflamed tissues through the proteolytic cleavage of an exposed reactive centre loop (RCL) by neutrophil elastase (NE). We previously demonstrated that RCL-localised Asn347-linked N-glycans impact NE proteolysis, but a comprehensive structure-function characterisation of the RCL glycosylation is still required to better understand CBG glycobiology. Herein, we firstly performed RCL-centric glycoprofiling of serum-derived CBG to elucidate the Asn347-glycans and then used molecular dynamics simulations to study their impact on NE proteolysis. Importantly, we also identified novel O-glycosylation (di/sialyl T) across four RCL sites (Thr338/Thr342/Thr345/Ser350) of serum CBG close to the NE-targeted Val344-Thr345 cleavage site. A restricted N- and O-glycan co-occurrence pattern on the RCL involving exclusively Asn347 and Thr338 glycosylation was experimentally observed and supported in silico by modelling of a CBG-GalNAc-transferase (GalNAc-T) complex with various RCL glycans. GalNAc-T2 and -T3 abundantly expressed by liver and gall bladder, respectively, showed in vitro a capacity to transfer GalNAc (Tn) to multiple RCL sites suggesting their involvement in RCL O-glycosylation. Recombinant CBG was then used to determine roles of RCL O-glycosylation through longitudinal NE-centric proteolysis experiments, which demonstrated that both sialo- (disialyl T) and asialo-glycans (T) decorating Thr345 inhibit NE proteolysis. Synthetic RCL O-glycopeptides expanded on these findings by showing that Thr345-Tn and Thr342-Tn confer strong and moderate protection against NE cleavage, respectively. Molecular dynamics substantiated that short Thr345-linked O-glycans abrogate NE interactions. In conclusion, we report on strategically-positioned and biologically-relevant CBG RCL glycans, which improve our understanding of mechanisms governing cortisol delivery to inflamed tissues.

Corticosteroid-Binding Globulin (SERPINA6) Consolidates Sexual Dimorphism of Adult Rat Liver.

Produced by the liver, corticosteroid-binding globulin (CBG) regulates the plasma distribution and actions of glucocorticoids. A sex difference in pituitary growth hormone secretion patterns established during puberty in rats results in increased hepatic CBG production and 2-fold higher plasma corticosterone levels in females. Glucocorticoids control hepatic development and metabolic activities, and we have therefore examined how disrupting the SerpinA6 gene encoding CBG influences plasma corticosterone dynamics, as well as liver gene expression in male and female rats before and after puberty. Comparisons of corticosterone plasma clearance and hepatic uptake in adult rats, with or without CBG, indicated that CBG limits corticosterone clearance by reducing its hepatic uptake. Hepatic transcriptomic profiling revealed minor sex differences (207 differentially expressed genes) and minimal effect of CBG deficiency in 30-day-old rats before puberty. While liver transcriptomes in 60-day-old males lacking CBG remained essentially unchanged, 2710 genes were differentially expressed in wild-type female vs male livers at this age. Importantly, ∼10% of these genes lost their sexually dimorphic expression in adult females lacking CBG, including those related to cholesterol biosynthesis, inflammation, and lipid and amino acid catabolism. Another 203 genes were altered by the loss of CBG specifically in adult females, including those related to xenobiotic metabolism, circadian rhythm, and gluconeogenesis. Our findings reveal that CBG consolidates the sexual dimorphism of the rat liver initiated by sex differences in growth hormone secretion patterns and provide insight into how CBG deficiencies are linked to glucocorticoid-dependent diseases.

Discovery and validation of protein biomarkers for monitoring the effectiveness of drug treatment for major depressive disorder

Major depressive disorder (MDD) has a high prevalence worldwide. Although the economic burden of depression increases annually, the proportion of patients with MDD receiving treatment did not increase between 2010 and 2018, suggesting an unmet treatment need. The burden of long-term treatment for depression is borne by patients. In this context, biomarkers associated with drug-treatment responses can be used as reference indicators to reduce unnecessary treatment and costs. Changes in biomolecules in response to drug treatment for depression and drug-treatment response markers have been studied extensively. The Hamilton Depression Rating Scale (HAM-D) is mainly used as an indicator of response and remission; however, it is difficult to determine whether the medication contributes to recovery when evaluating the effect of drug treatment for depression based on this assessment. Therefore, it is necessary to monitor the effect of medication compared to normal health conditions. Here, serum protein levels were compared using liquid chromatography-tandem mass spectrometry among a group of patients with depression who did not receive medication, a group of patients receiving medication, and a control group. Eight selected biomarkers, including Apolipoproteins A-I, Complement factor H, Complement C5, Complement C1q subcomponent subunit B, Alpha-2-HS-glycoprotein, Complement C1q subcomponent subunit C, Vitamin D-binding protein and Corticosteroid-binding globulin were distinguished between disease states, and protein levels in the drug-treated group were similar to those in the control group. These markers can be used to monitor the effectiveness of drug treatment.

Adrenal Suppression in Children During the Treatment for Acute Lymphoblastic Leukemia Beyond Induction.

Adrenal suppression (AS) is an iatrogenic, life-threatening condition that can occur after glucocorticoid exposure. Despite recognition that AS occurs after induction phase treatment in children with acute lymphoblastic leukemia (ALL), the risk of AS in phases beyond induction is unknown. We conducted a pilot study in pediatric patients with ALL to ascertain whether the risk of AS persists in post-induction phases of treatment. Patients diagnosed between 12 months to younger than 18 years with B or T-ALL and starting any new phase of treatment were eligible for the study. Relapsed or infant ALL were excluded. Low dose ACTH stimulation testing (LDST), measurement of albumin and cortisol binding globulin were performed in all patients. Screening for symptoms of AS was done. Twenty-four patients enrolled in the study. One was diagnosed with clear AS. Five others had a borderline cortisol peak, representing possible mild AS. Symptoms were nonspecific and did not help distinguish patients with normal LDST from those with borderline or abnormal results. Patients on treatment for ALL continue to be at risk of AS beyond induction treatment. Although this risk appears small, physicians must be vigilant as patients may be asymptomatic but could develop adrenal crisis during treatment.

Effect of The Rs-10 Radioprotector on Protein-Steroid Interaction in Irradiated Animals with Biphasic Adrenocortical Response to Irradiation

The article is devoted to the influence of RS-10 radioprotector on the protein-steroid interaction in irradiated animals. Introduction. Increasing threats to the radiation safety of the population is now causing the need for comprehensive studies of the anti-beam properties of chemical radioprotectors. The aim of the study is to study the effect of the RS-10 radioprotector on protein-steroid interaction in irradiated guinea pigs with biphasic adrenocortical response to irradiation. Study methods: experiments were conducted on 146 guinea pigs weighing 300-350 g, which were exposed to total ƴ radiation at a dose of 3.5 Gy and 4.5 Gy at a dose rate of 5.76 Gy/min, which caused them radiation disease of II and III severity. Experimental animals were injected intraperitoneally with RS-10 (chitosan bitartrate) 15 minutes before irradiation. Control animals were administered an equal volume of saline. The total plasma content of 11-oxycorticosteroids (11-OKS) was determined by the fluorometric method of Guillemin et al. in the author's modification. The binding capacity of corticosteroid binding globulin (CSG) was determined by gel filtration of De Moor at al. in the author's modification. Conclusions. Prophylactic administration of RS-10 to irradiated animals with a two-phase adreno-cortical reaction to radiation causes a later onset of secondary hypercorticism in the midst of radiation sickness in animals. Prophylactic administration of RS-10 before irradiation reduces the level of free hormone and leads to a decrease in hypercorticism, increasing the reserve capabilities of the binding ability of the CSG at the height of radiation sickness. A leading role in the mechanism of reducing affected hypercorticism under protective conditions has a lesser degree of impairment of the binding capacity of the CSG, rather than a change in the total level of 11-OKS in the blood.

OR30-02 Salivary Cortisol Response To The High Dose ACTH Stimulation Test Provides A Reliable Alternative To Serum Cortisol Measurement In The Evaluation of Suspected Hypoadrenalism, And Is Unaffected By Cortisol-Binding Concentration

Abstract Disclosure: N. El-Farhan: None. S. Rees: None. S. Tennant: None. C. Evans: None. A. Rees: None. Context The serum total cortisol response to the ACTH stimulation test is widely used to assess adrenocortical function but is affected in conditions of altered cortisol-binding globulin (CBG) concentration. Salivary cortisol reflects free cortisol concentrations and may offer a reliable alternative. Objectives: 1. To establish the salivary cortisol response to the high dose ACTH stimulation test in healthy volunteers and in patients with altered CBG concentrations. 2. To evaluate the performance of a lower reference limit (LRL) determined in healthy volunteers in patients with suspected hypoadrenalism. Design: A high dose (250 µg) intravenous ACTH stimulation test was undertaken in 139 (60 male, 79 female) healthy volunteers, 24 women taking an oestradiol-containing oral contraceptive pill (OCP females), 10 patients with low serum protein concentration secondary to the nephrotic syndrome or liver cirrhosis (LP patients) and 29 patients with suspected hypoadrenalism (SH patients). Salivary cortisol was measured by liquid chromatography-tandem mass spectrometry. The mean and estimated LRL of the 30-minute salivary cortisol response to ACTH stimulation (mean - 1.96 SD) were derived from log-transformed concentrations. The LRL was subsequently applied as a diagnostic cut-off in SH patients. Results: CBG concentrations were 58 [42-81] mg/L), 64 mg/L [43-95], 41 [28-60] mg/L and116 [84-159] mg/L in male volunteers, female volunteers, LP patients and OCP females, respectively. The mean 30-minute salivary cortisol concentration was 19.3 [2.5th-97.5th percentile 10.3-36.2] nmol/l in healthy volunteers, with no difference between genders. Corresponding values were not different in OCP females (19.7 [9.5-41.2] nmol/l; p=0.59) and LP patients (19.0 [7.7-46.9] nmol/l; p=0.97), in contrast to 30-minute mean serum cortisol responses which differed between healthy female volunteers (555 [421-731] nmol/l) and OCP females (869 [649-1162] nmol/l; p<0.001). Overall diagnostic agreement between 30-minute salivary and serum responses in patients undergoing evaluation for SH was high (79%). Conclusions: Salivary cortisol response to intravenous ACTH stimulation offers a reliable alternative to serum cortisol measurement in the assessment of patients with suspected hypoadrenalism and may be especially useful in conditions of altered CBG concentration. Presentation: Sunday, June 18, 2023

SAT299 Comparison Of Plasma Cortisol-, Salivary Cortisol- And Salivary Cortisone-response To The Short Synacthen Test In Women Using Oral Contraceptives

Abstract Disclosure: N. Bäcklund: None. S. Lundstedt: None. T. Olsson: None. P.M. Dahlqvist: None. G. Brattsand: None. Introduction: The short Synacthen test (SST) is a cornerstone in the diagnosis of adrenal insufficiency (AI). However, cortisol levels in serum or plasma may be misleadingly elevated by estrogen containing oral contraceptives (OCs), due to increased levels of cortisol binding protein (CBG). This may falsely declare a woman with AI to be cortisol sufficient. Salivary cortisol and cortisone closely correlate with the unbound fraction of plasma cortisol and is thus less likely to be influenced by variations in CBG levels. Our hypothesis was that the salivary cortisol and cortisone response to SST would be similar in women with and without OC use. Materials and methods: A standard intravenous 250 µg SST was performed in 87 women without known diseases or medications affecting the cortisol axis, 41 using OCs containing ethinylestradiol and 46 controls. Plasma cortisol was analyzed by Roche Elecsys Cortisol II assay and salivary cortisol and cortisone by LC-MS/MS in samples collected at baseline (time 0), and 30 and 60 minutes after Synacthen injection. The effect of OCs upon plasma cortisol, salivary cortisol and salivary cortisone was assessed by a two-way ANOVA with sampling time after SST as repeated measure. Results: There was an overall effect of OCs on plasma cortisol, but not on salivary cortisol or cortisone. Plasma cortisol levels were considerably higher in the OC group vs. controls at all time points; +150% at 0 minutes; +90% at 30 minutes; and +86% at 60 minutes. There was a significant interaction between OC use and sample time point for both salivary cortisol and cortisone. Mean salivary cortisol in women using OCs was 37% higher vs. controls at 0 minutes but was instead lower in the OCs group at 30 and 60 minutes after SST (-13% and -11%, respectively). Similarly, mean salivary cortisone was also slightly higher in the OC group than controls at baseline (+13%) and somewhat lower at 30 and 60 minutes (-6% and -7%). Conclusion: Plasma cortisol levels during an SST were significantly elevated in women using OCs containing estrogen whereas OC effects upon salivary cortisol and cortisone levels were modest, especially for salivary cortisone. Analysis of salivary cortisone is a promising alternative to plasma cortisol for diagnosis of AI in women using OCs. Presentation: Saturday, June 17, 2023

FRI268 Late Onset Polyglandular Autoimmune Syndrome Type 2

Abstract Disclosure: M.S. Nicholson: None. A. Barnett: None. A 66-year old white female was admitted for weakness, acute kidney injury, and hypotension. This is her 3rd hospital or ER visit in the last 12 months for similar complaints. She has a 25 year history of type 2 diabetes on insulin and oral therapy and 30 year history of hypothyroidism on levothyroxine 75 mcg daily. She was on oral estrogen replacement therapy for post-menopausal symptoms with a hysterectomy in her early 50s. She has a sister with type 2 diabetes on oral meds and hypothyroidism. She has a brother with type 1 diabetes. Her serum sodium was 135 mmol/L (135-145), potassium was 5.4 mEq/L (3.5 -5.1), and calcium was 9.2 (8.5-10.1). Her Creatinine was 1.2 with a GFR of 48. A random cortisol in the ED was 9.2 (no ref range). Blood pressure was low and she was tachycardic and her weight was 68 kg. She was a well developed female with a a tanned complexion. Areas of vitiligo were noted on her arms. A cosyntropin stimulation test was done midday with a baseline, 30, and 60 minute cortisol levels of 9.2, 8.8, and 9.3 respectively. Baseline ACTH was 877.6 pg/mL (7.2-63.6). Her TSH was 4.09 mIU/mL (0.358-3.74) and free T4 was 1.29 ng/dL (0.76-1.46). DHEA-S was 14 mcg/dL (13-130). She was started on stress dose steroids with rapid improvement in BP, hyponatremia, and symptoms. GAD-65 antibodies were above 250 IU/mL and 21-hydroxylase antibodies were positive. Her TPO antibodies were negative. Non-insulin diabetes medications were stopped and she was discharged home after stabilization on prednisone 5 mg daily and fludrocortisone 0.1 mg daily. This patient has an atypical presentation of polyglandular autoimmune syndrome type 2 (PAS2). She presented with an Addisons crisis at the age of 66. She was already diagnosed with hypothyroidism and insulin requiring diabetes and evidence of vitiligo. A majority of patients with PAS2 are female and present in their 20s to 40s with primary adrenal insufficiency and primary hypothyroidism. Her initial manifestation was hypothyroidism and then diabetes and vitiligo with adrenal insufficiency many years later. Her random cortisol was not suppressed and this lead to a delay in her diagnosis. This was likely due to oral estrogen therapy raising cortisol-binding globulin. Her elevated baseline ACTH and lack of response to ACTH stimulation confirmed her diagnosis of primary adrenal insufficiency. An ACTH stimulation test was repeated as an outpatient with similar response. This case highlights the importance of provocative testing for adrenal disorders and testing for autoimmune causes of endocrine disorders when patients are not responding as expected. Presentation: Friday, June 16, 2023

Salivary Cortisol Response to ACTH Stimulation Is a Reliable Alternative to Serum Cortisol in Evaluating Hypoadrenalism.

The serum total cortisol response to the ACTH stimulation test is widely used to assess adrenocortical function but is affected by changes in cortisol-binding globulin (CBG) concentration. Salivary cortisol reflects free cortisol concentrations and may offer a reliable alternative. (1) To establish the salivary cortisol response to ACTH stimulation in healthy volunteers and patients with altered CBG concentrations; (2) to evaluate the performance of a lower reference limit (LRL) determined in healthy volunteers in patients with suspected hypoadrenalism (SH-patients). A 250 µg ACTH stimulation test was undertaken in 139 healthy volunteers, 24 women taking an estradiol-containing oral contraceptive pill (OCP-females), 10 patients with low serum protein concentration (LP-patients), and 30 SH-patients. Salivary cortisol was measured by liquid chromatography-tandem mass spectrometry. Mean and LRL of the 30-minute salivary cortisol response (mean-1.96 standard deviation) were derived from log-transformed concentrations. The LRL was applied as a diagnostic cut-off in SH-patients, with comparison to the serum response. Mean CBG concentrations (range) were 58 (42-81) mg/L, 64 (43-95) mg/L, 41 (28-60) mg/L, and 116 (84-159) mg/L in males, females, LP-patients, and OCP-females, respectively. The mean 30-minute salivary cortisol concentration was 19.3 (2.5th-97.5th percentile 10.3-36.2) nmol/L in healthy volunteers. Corresponding values were not different in OCP-females [19.7 (9.5-41.2) nmol/L; P = .59] or LP-patients [19.0 (7.7-46.9) nmol/L; P = .97]. Overall diagnostic agreement between salivary and serum responses in SH-patients was 79%. Salivary cortisol response to ACTH stimulation offers a reliable alternative to serum and may be especially useful in conditions of altered CBG concentration.

Stress biomarkers in adult patients with drug-resistant epilepsy on a modified Atkins diet: A prospective study.

Ketogenic diets like the modified Atkins diet (MAD) are increasingly used in patients with refractory epilepsy. For epilepsy patients, stress is a well-known seizure-precipitating factor. New possibilities for measuring biomarkers of stress are now available. The purpose of this study was to investigate the impact of MAD on endocrine stress biomarkers. Forty-nine patients with drug-resistant epilepsy were investigated at baseline and after 12 weeks on MAD. Cortisol and cortisol-binding globulin (CBG) were measured and free cortisol index (FCI) calculated. We also measured metanephrine, normetanephrine, and methoxytyramine, all markers of epinephrine, norepinephrine, and dopamine, respectively. Changes were analyzed according to sex and antiseizure medications. The different markers at baseline and after 12 weeks of MAD treatment were correlated with seizure frequency and weight loss, respectively. The change in total cortisol was modest after 12 weeks on the diet (from 432.9 nmol/L (403.1-462.7)) to 422.6 nmol/L (384.6-461.0), P = 0.6). FCI was reduced (from 0.39 (0.36-0.42) to 0.34 (0.31-0.36), P = 0.001). CBG increased during the study (from 1126.4 nmol/L (1074.5-1178.3) to 1272.5 nmol/L (1206.3-1338.7), P < 0.001). There were no changes in the metanephrines after 12 weeks on the diet. The decrease in FCI was significant only in women, and only observed in patients using nonenzyme-inducing ASMs. We did not find any correlation between cortisol, CBG, or FCI levels and seizure frequency. After being on MAD for 12 weeks, FCI decreased significantly. The reduction in FCI may reflect reduced stress, but it may also be an effect of increased CBG. The reasons behind these alterations are unknown. Possibly, the changes may be a result of a reduction in insulin resistance and thyroid hormone levels. Treatment with MAD does not seem to influence "fight or flight" hormones.

The free cortisol calculated: correlation with the free cortisol concentrations measured with liquid chromatography-tandem mass spectrometry after equilibrium dialysis and establishment of reference intervals

Background Changes in cortisol binding globulin (CBG) impact the total serum cortisol concentration and affect the accurate assessment of adrenal function. Free biologically cortisol can be calculated using different equations or directly measured after complicated procedures. Methods The free cortisol index (FCI) obtained using the Bonte formula as well as the free cortisol concentration calculated (Coolens equation) were first estimated for 45 healthy workers. The CBG level was determined by a competitive radioimmunoassay and the total cortisol concentration, was measured with an electrochemiluminescent assay. The correlations between FCI, the free cortisol concentrations calculated and the free cortisol levels measured with liquid chromatography-tandem mass spectrometry after equilibrium dialysis were studied for those 45 samples. Reference limits were established on 158 healthy hospital workers and patients with serum samples collected between 7:30 am and 10 am. Results The FCI as well as the free cortisol concentrations calculated obtained for the 45 samples correlated significantly with the free cortisol levels measured. Although the cortisol and CBG levels were statistically higher in women using contraceptives compared with women not taking them as well as men, the calculated FCI and free cortisol concentrations did not differ between these groups. The medians (P2.5-P97.5) obtained for the 158 healthy workers were respectively 26.4% (12.3-51.6%) and 10.6 nmol/L (4.3-26.7 nmol/L). Conclusions This study highlighted a significant correlation between the FCI, the free cortisol concentrations calculated and the free cortisol levels measured with LC-MS/MS, it has also allowed the establishment of reference intervals for calculated FCI and free cortisol.