Repeatability of endocrine traits and dominance rank in female guinea pigs

Background Glucocorticoids (e.g. cortisol) are associated with variation in social behavior, and previous studies have linked baseline as well as challenge-induced glucocorticoid concentrations to dominance status. It is known that cortisol response to an acute challenge is repeatable and correlates to social behavior in males of many mammal species. However, it is unclear whether these patterns are also consistent for females. The aim of this study was to investigate whether baseline and response cortisol concentrations are repeatable in female guinea pigs (Cavia aperea f. porcellus) and whether dominance rank is stable and correlated to baseline cortisol concentration and/or cortisol responsiveness. Results Our results show that cortisol responsiveness (after 1 h: R = 0.635, 95% CI = 0.229, 0.927; after 2 h: R = 0.764, 95% CI = 0.433, 0.951) and dominance rank (R = 0.709, 95% CI = 0.316, 0.935) of females were significantly repeatable after six weeks but not correlated. Baseline cortisol was not repeatable (R = 0, 95% CI = 0, 0.690) and also did not correlate to dominance rank. Furthermore, the difference in repeatability estimates of baseline and response values was due to high within-individual variance of baseline cortisol concentration; the amount of between-individual variance was similar for baseline cortisol and the two measures of cortisol responsiveness. Conclusions Females occupying different dominance ranks did not have long-term differences in cortisol concentrations, and cortisol responsiveness does not seem to be significantly involved in the maintenance of dominance rank. Overall, this study reveals the remarkable stability of cortisol responsiveness and dominance rank in a female rodent, and it remains an open question whether the magnitude of cortisol responsiveness is adaptive in social contexts for females.

Bedtime Salivary Cortisol and Depressive Symptoms in Older Adults Living With Dementia

The dysregulation of cortisol has been associated with depressive symptoms in older adults. To date, no prospective longitudinal studies have examined whether salivary cortisol is a risk factor for depressive symptoms in persons living with dementia (PLWD). With a sample of 123 PLWD, baseline salivary cortisol was collected at awaking, 30 minutes after awaking, and bedtime. Depressive symptoms were assessed at baseline and the four-week follow-up. Cortisol indicator were centered. Baseline bedtime cortisol level was significantly associated with depressive symptoms in a curvature style while controlling age, gender, and baseline depressive symptoms (𝛽=3.76 for linear term and 𝛽=-1.57 for quadratic term, both ps<0.04). No other baseline cortisol measures were significant prospective predictors. Our results suggest the bedtime cortisol was a significant risk factor for depressive symptoms in PLWD. These findings suggest that bedtime cortisol may play a role in the etiology of depressive symptoms in PLWD.

Hypercortisolism in patients with cholestasis is associated with disease severity

Background Cholestasis might lead to an impairment of adrenal function as suggested by in vitro and in vivo data as well as by clinical findings. Bile acid and adrenal steroid metabolism not only share the receptors farnesoid X receptor (FXR) and the G protein-coupled bile acid receptor 1 (TGR5), but supraphysiological bile acid levels were found to stimulate steroidogenesis independent of FXR and TGR5. Our previous experimental findings revealed that mice fed bile acids or subjected to common bile duct ligation develop hypercortisolemia. We thus aimed to assess adrenal gland function in patients with cholestasis. Methods Adrenal gland function was assessed in 36 patients with cholestasis and in 32 patients without cholestasis by measuring total serum cortisol, adrenocorticotropic hormone (ACTH), as well as the increase of cortisol 20 and 30 min after administration of 1 µg of ACTH. Bile acid levels and bile acid pool composition were determined by high-resolution mass spectrometry. Results Patients with cholestasis per definition had markedly elevated levels of alkaline phosphatase (AP), bilirubin and serum bile acids. Baseline cortisol and maximum cortisol after ACTH stimulation were significantly higher in patients with cholestasis compared to controls. Increase of cortisol after ACTH stimulation and ACTH did not differ. In the cholestasis group, baseline cortisol correlated with bilirubin but not with AP, total serum bile acids and levels of conjugated and unconjugated bile acid species. Patients with duration of cholestasis < 6 months (n = 30) had significantly higher baseline cortisol levels than those with long standing cholestasis (> 6 months), together with higher bilirubin levels. Conclusions We find no evidence of adrenal insufficiency in non-cirrhotic patients with cholestasis. In contrast, patients with cholestasis show hypercortisolism associated with disease severity as mirrored by levels of bilirubin. Lack of ACTH increase in cholestasis suggests a direct effect of cholestasis on adrenals and not on the pituitary gland. Further studies are needed to elucidate the mechanism of cortisol elevation in patients with cholestasis and its clinical significance.

Low heritability and high phenotypic plasticity of salivary cortisol in response to environmental heterogeneity in fur seals

Individuals are unique in how they interact with and respond to their environment. Correspondingly, unpredictable challenges or stressors often produce an individualized response of the hypothalamic-pituitary-adrenal axis and its downstream effector cortisol. We used a fully crossed, repeated measures design to investigate the factors shaping individual variation in baseline cortisol and cortisol responsiveness in Antarctic fur seal pups and their mothers. Saliva samples were collected from focal individuals at two breeding colonies, one with low and the other with high population density, during two consecutive years of contrasting food availability. Mothers and pups were sampled concurrently at birth and shortly before weaning, while pups were additionally sampled every 20 days. We found that heritability was low for both baseline cortisol and cortisol responsiveness, while within-individual repeatability and among-individual variability were high. A substantial proportion of the variation in baseline cortisol could be explained in pups and mothers by a combination of intrinsic and extrinsic factors including sex, weight, day, season, and colony of birth. However, the same variables explained little of the variation in cortisol responsiveness. Our findings provide detailed insights into the individualization of endocrine phenotypes in a wild pinniped.

Type 4 Renal Tubular Acidosis (RTA) Induced by Spironolactone Use in Secondary Adrenal Insufficiency

Type 4 RTA is caused by either decreased aldosterone production or resistance. Primary adrenal insufficiency results in decreased aldosterone whereas spironolactone can cause aldosterone resistance1. We present a case of spironolactone-induced type 4 RTA in a patient with suspected primary adrenal insufficiency. A 70-year-old female with liver cirrhosis on spironolactone and chronic bronchitis on inhaled steroids (ICS) presented for altered mental status. Laboratories showed hyponatremia 131 mmol/L (135–145 mmol/L) and hyperammonemia 113 µmol/L (11–51 µmol/L). She was successfully treated with oral lactulose for hepatic encephalopathy. However, on day 3, she developed worsening hyponatremia (126 mmol/L) and hyperkalemia 5.8 mmol/L (3.5–5.4 mmol/L). Spironolactone was discontinued, and hyperkalemia improved after medical treatment. Nonetheless, hyperkalemia recurred with worsening hyponatremia (125 mmol/L), hypoglycemia (57 mg/dL), and mild non-anion gap metabolic acidosis without other signs or symptoms of adrenal insufficiency. On day 5, her morning cortisol was 1.5 µg/dL (5–20 µg/dL), with ACTH 11 pg/mL (6–70 pg/mL). Her hyperkalemia persisted (6.3–6.8 mmol/L), and she was started on oral patiromer. Due to suspected adrenal insufficiency, she received dexamethasone 10 mg daily, and endocrinology was consulted. On day 7, an ACTH stimulation test (250 µg IV) showed a baseline ACTH &lt;3 pg/mL, baseline cortisol 0.7 µg/dL (3–15 µg/dL), cortisol 30 minutes 9.9 µg/dL, and 60 minutes 12.2 µg/dL, consistent with incomplete response attributed to the supraphysiologic dexamethasone versus chronic ICS. On day 8, endocrinology discontinued dexamethasone and enoxaparin, and started hydrocortisone 10 mg orally in AM and 5 mg in PM. Aldosterone (measured at day 6) was 7.2 ng/dL (&lt;= 31.0 ng/dL), renin activity 3.1 ng/mL/hr (0.5–4.0 ng/mL/hr), and aldosterone/renin ratio 2.3 (&lt;= 25) consistent with hyporeninemic hypoaldosteronism since aldosterone and renin were inappropriately normal for the hyperkalemia. Repeat cosyntropin test on day 11 showed low ACTH (3 pg/mL), low baseline cortisol 1.1 µg/dL, cortisol 30 minutes 7.9 µg/dL, and 60 minutes 11.2 µg/dL, consistent with secondary adrenal insufficiency, ascribed to chronic ICS. Potassium level normalized seven days after spironolactone discontinuation, related to its approximate duration of action1. The patient was discharged with hydrocortisone 10 mg daily, and spironolactone was permanently discontinued. Spironolactone use can result in type 4 RTA due to aldosterone resistance and mimic mineralocorticoid deficits characteristic of primary adrenal insufficiency. 1. O’Connell JE, Colledge NR. Type IV renal tubular acidosis and spironolactone therapy in the elderly. Postgrad Med J. 1993;69(817):887–889.

Cortisol responsiveness and dominance rank, but not baseline cortisol level, are repeatable traits in adult female guinea pigs

Social interactions among group members often lead to the formation of stable dominance hierarchies. Glucocorticoids (i.e. cortisol) have been proposed as an endocrine mechanism underlying social behavior, and previous studies have linked baseline as well as challenge glucocorticoid concentrations to dominance rank. Since the importance of rank on fitness differs between males and females, selection pressures acting on the underlying endocrine mechanisms may differ between the sexes. In male guinea pigs, for example, it is known that cortisol responsiveness mediates social behavior and that dominance rank and cortisol responsiveness are stable within individuals over time. It is unclear whether this is also the case for female guinea pigs. Thus the aim of this study was to investigate whether cortisol concentrations are repeatable in female guinea pigs and whether female rank is correlated to baseline cortisol concentrations or cortisol responsiveness. We show that cortisol responsiveness and dominance rank were significantly repeatable but not correlated in female guinea pigs. Furthermore, baseline cortisol was not repeatable and also did not correlate to dominance rank. Our results demonstrate that baseline cortisol and cortisol responsiveness represent different biological processes; cortisol responsiveness reflects a stable trait while baseline cortisol likely fluctuates with current state. Furthermore, cortisol responsiveness as a mediator of aggressive behavior and dominance acquisition might not be important for maintaining dominance hierarchies in stable groups of females displaying minimal aggression. Overall, this study reveals the remarkable stability of cortisol responsiveness and dominance rank in an adult female rodent and lays the groundwork for future investigations into the causes and consequences of this individual variation.

New Cutoffs for the Biochemical Diagnosis of Adrenal Insufficiency after ACTH Stimulation using Specific Cortisol Assays

Context The normal cortisol response 30 or 60 minutes after cosyntropin (ACTH[1–24]) is considered to be ≥18 μg/dL (500 nmol/L). This threshold is based on older serum cortisol assays. Specific monoclonal antibody immunoassays or LC-MS/MS may have lower thresholds for a normal response. Objective To calculate serum cortisol cutoff values for adrenocorticotropic hormone (ACTH) stimulation testing with newer specific cortisol assays. Methods Retrospective analysis of ACTH stimulation tests performed in ambulatory and hospitalized patients suspected of adrenal insufficiency (AI). Serum samples were assayed for cortisol in parallel using Elecsys I and Elecsys II immunoassays, and when volume was available, by Access immunoassay and LC-MS/MS. Results A total of 110 patients were evaluated. Using 18 μg/dL as the cortisol cutoff after ACTH stimulation, 14.5%, 29%, 22.4%, and 32% of patients had a biochemical diagnosis of AI using the Elecsys I, Elecsys II, Access, and LC-MS/MS assays, respectively. Deming regressions of serum cortisol were used to calculate new cortisol cutoffs based on the Elecsys I cutoff of 18 μg/dL. For 30-minute values, new cutoffs were 14.6 μg/dL for Elecsys II, 14.8 μg/dL for Access, and 14.5 μg/dL for LC-MS/MS. Baseline cortisol &lt;2 μg/dL was predictive of subnormal stimulated cortisol values. Conclusion To reduce false positive ACTH stimulation testing, we recommend a new serum cortisol cutoff of 14 to 15 μg/dL depending on the assay used (instead of the historical value of 18 μg/dL with older polyclonal antibody assays). Clinicians should be aware of the new cutoffs for the assays available to them when evaluating patients for AI.

Sex, Type of Surgery, and Surgical Site Infections Are Associated with Perioperative Cortisol in Colorectal Cancer Patients

Excessive endocrine response to trauma negatively affects patients’ well-being. Cortisol dynamics following robot-assisted colorectal surgery are unknown. We aimed at determining the impact of cancer pathology and surgery-related factors on baseline cortisol levels and analyzed its time-profile in colorectal cancer patients undergoing open or robot-assisted surgery. Cortisol levels were measured using liquid chromatography quadrupole time-of-flight mass spectrometry. Baseline cortisol was not associated with any patient- or disease-related factors. Post-surgery cortisol increased by 36% at 8 h and returned to baseline on postoperative day three. The cortisol time profile was significantly affected by surgery type, estimated blood loss, and length of surgery. Baseline-adjusted cortisol increase was greater in females at hour 8 and in both females and patients from open surgery group at hour 24. Solely in the open surgery group, cortisol dynamics paralleled changes in interleukin (IL)-1β, IL-10, IL-1ra, IL-7, IL-8 and tumor necrosis factor (TNF)-α but did not correlate with changes in IL-6 or interferon (IFN)-γ at any time-point. Cortisol co-examined with C-reactive protein was predictive of surgical site infections (SSI) with high accuracy. In conclusion, patient’s sex and surgery invasiveness affect cortisol dynamics. Surgery-induced elevation can be reduced by minimally invasive robot-assisted procedures. Cortisol and C-reactive protein as SSI biomarkers might be of value in the evaluation of safety of early discharge of patients.