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Warrick J Inder

While the ACTH1–24 test has some well-documented shortcomings, it is the most widely used test to diagnose primary and secondary adrenal insufficiency. However, this synthetic ACTH preparation is not readily available in some countries. Research from India has demonstrated that using a long-acting porcine sequence ACTH has similar diagnostic performance to ACTH1–24 at around 25% of the cost. This may allow access to a robust test for adrenal insufficiency to developing countries and potentially allow thousands of patients to be identified and appropriately treated.

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Andrea Lamprecht, Jane Sorbello, Christina Jang, David J Torpy and Warrick J Inder

Objective

To evaluate pituitary function, sexual function and quality of life (QoL) in patients on oral or transdermal opioids.

Design and methods

Cross-sectional study comparing pituitary function, QoL and sexual function in people on long-term opioid therapy (n = 40) vs an age- and sex-matched control group (n = 25). Baseline pituitary function was assessed on blood samples collected prior to 0900 h. Further testing with corticotropin (250 µg IV) and metyrapone (30 mg/kg) stimulation tests was undertaken on participants with serum cortisol <250 nmol/L. Validated questionnaires completed to assess QoL, fatigue and sexual function.

Results

Secondary adrenal insufficiency (SAI) was identified on the basis of a failed stimulation test in 22.5% of opioid users vs no controls (P = 0.01). Opioid users with SAI had a higher median morphine-equivalent daily dose (MEDD), P = 0.037 – 50% with MEDD >200 mg and 0% with MEDD <60 mg had SAI. Among male participants, testosterone was inversely associated with BMI (P = 0.001) but not opioid use. A non-significant trend to low testosterone <8 nmol/L in male opioid users (11/24 opioid users vs 2/14 control, P = 0.08) suggests a small subgroup with opioid-induced androgen deficiency. Opioid users had greater fatigue, reduced quality of life in all subsections of the SF-36 and impaired sexual function in both males and females (all scores P < 0.001 compared to controls).

Conclusion

Long-term opioid therapy was associated with dose-related SAI in over 20% of chronic pain patients and is associated with poor quality of life, fatigue and sexual dysfunction. Obesity confounds the interpretation of opioid-induced male androgen deficiency.

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Christina Jang, Varuni R Obeyesekere, Frank P Alford and Warrick J Inder

Objective

Cortisol has been traditionally implicated in the causation of peri-operative skeletal muscle (SkM) insulin resistance, but cortisol levels return to normal within 72 h of surgery. Tissue cortisol bioactivity may be prolonged by local upregulation of the enzyme 11βHSD1. We aimed to investigate the changes of SkM 11βHSD1 enzyme activity and mRNA expression, relative to plasma cortisol, insulin and glucose levels following elective abdominal surgery.

Patients and design

Eight non-diabetic subjects (two male, six female) underwent serial plasma hormone sampling and muscle biopsy of vastus lateralis at baseline and on day 5 following elective laparoscopic cholecystectomy.

Methods

SkM 11βHSD1 and H6PDH mRNA levels were measured by quantitative RT-PCR and enzyme activity by % conversion of 3H cortisone to cortisol. Plasma glucose, insulin, free fatty acids (FFA), tumour necrosis factor-α and cortisol by standardised assays.

Results

Compared with baseline, SkM 11βHSD1 activity was significantly increased on day 5 after surgery (14.7±2.1 vs 20.4±3.2%, P=0.005). Neither 11βHSD1 nor H6PDH mRNA levels were altered after surgery. Plasma cortisol (P=0.027), FFA (P=0.01) and glucose (P=0.004) rose rapidly following surgery and had returned to baseline values by 24 h post-surgery. There was no significant change in plasma insulin.

Conclusions

This is the first study to demonstrate an upregulation of SkM 11βHSD1 activity in response to a physiological stressor. Sustained activation of this enzyme may increase tissue cortisol bioactivity.

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Johanna L Barclay, Carolyn J Petersons, Sahar Keshvari, Jane Sorbello, Brenda L Mangelsdorf, Campbell H Thompson, Johannes B Prins, Morton G Burt, Jonathan P Whitehead and Warrick J Inder

Objective

Thrombospondin-1 (TSP1) is a matricellular protein whose gene expression has previously been shown to increase acutely after exposure to dexamethasone in vitro. The aim of this study was to determine if TSP1 is altered by acute and chronic states of glucocorticoid excess in human subjects.

Design and methods

Three studies have been undertaken to assess the difference or change in TSP1 in response to altered glucocorticoid activity: i) an acute interventional study assessed the effects of a single 4 mg dose of dexamethasone in 20 healthy volunteers; ii) a cross-sectional study compared plasma TSP1 in 20 healthy volunteers and eight patients with Cushing's syndrome; iii) an interventional study assessed the effect on plasma TSP1 of an increase in hydrocortisone dose from ≤20 mg/day to 30 mg/day for 7 days in 16 patients with secondary adrenal insufficiency.

Results

In healthy volunteers, 4 mg dexamethasone significantly increased peripheral blood mononuclear cell (PBMC) TSP1 mRNA levels (P<0.0001) and plasma TSP1 concentrations (P<0.0001), peaking at 12 h. Median (interquartile range) plasma TSP1 was higher in Cushing's, 638 (535–756) ng/ml, than in healthy volunteers, 272 (237–336) ng/ml (P<0.0001). Plasma TSP1 >400 ng/ml diagnosed Cushing's syndrome with sensitivity of 100% and specificity of 85%. The higher hydrocortisone dose increased plasma TSP1 from 139 (86–199) to 256 (133–516) ng/ml, (P<0.01) in patients with secondary adrenal insufficiency.

Conclusions

TSP1 is a glucocorticoid responsive protein in humans. Further research is required to determine if plasma TSP1 has a role as a glucocorticoid biomarker.