Currently, 2-3% of the population of the United Kingdom and United States of America receive glucocorticoid therapy. Significant adverse effects are not confined to chronic use; recurrent short-course administration is associated with increased morbidity and mortality. The adverse metabolic features associated with glucocorticoid use include obesity, skeletal muscle myopathy, hypertension, insulin resistance and diabetes and are collectively termed 'iatrogenic Cushing's syndrome'. The efficacy of glucocorticoid therapy is not in doubt, but there are no interventions to reduce their metabolic consequences. Within metabolic tissues (liver, skeletal muscle, adipose), 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) regenerates active glucocorticoid and therefore is able to tightly control the availability of glucocorticoids to activate the glucocorticoid receptor. In preclinical studies, the investigators have shown that 11β-HSD1 is critical in regulating the development of the adverse features associated with circulating glucocorticoid excess, endorsing our observations in a patient with Cushing's disease, who was protected from a classical phenotype due to a functional deficit in 11β-HSD1.

This study is the first clinical evaluation of the impact of the selective 11β-HSD1 inhibitor, AZD4017, in healthy volunteers taking exogenous glucocorticoids (prednisolone). The investigators propose that in tissues expressing high levels of 11β-HSD1, prednisolone action will be amplified, driving adverse effects within these tissues and have hypothesized that AZD4017 in humans will reduce the adverse metabolic consequences of Prednisolone administration without compromise to its anti-inflammatory action.

Our specific research objectives are:

1. To demonstrate the beneficial effect of the selective 11β-HSD1 inhibitor, AZD4017, upon the prednisolone-induced deterioration in metabolic phenotype, including glucose disposal and endogenous glucose production rates.
2. To determine the impact of AZD4017 on the anti-inflammatory actions of Prednisolone.
3. To identify the tissue-specific (skeletal muscle, adipose) mechanisms underpinning the response to Prednisolone therapy administered in conjunction with AZD4017.

The investigators will perform a randomized, double-blind placebo controlled study to determine if co-administration of the selective 11β-HSD1 inhibitor, AZD4017, limits the adverse effects of short-course exogenous glucocorticoid administration. 32 healthy male volunteers will have detailed metabolic investigations including 2-step hyperinsulinaemic euglycaemic clamps (with stable isotope measurements of lipid and carbohydrate metabolism), as well as assessment of skeletal muscle forearm glucose uptake. All volunteers will then be treated with Prednisolone (20mg daily) and randomized to the co-administration of placebo or AZD4017. After 1 week of therapy, all investigations will be repeated. Our hypothesis is that the adverse metabolic effects of Prednisolone will be reduced by co-administration of AZD4017.

Inclusion Criteria:

The following criteria apply to both arms and each volunteer who has a successful screening visit will be randomized to one of the arms defined above (see section 6): We estimate that we will need to screen 40-50 patients in order to achieve our recruitment target.

• Male volunteers without diabetes (HbA1C < 48mmol/mol at screening)
• BMI 20-30kg/m2
• Age 18-60years
• For individuals identified from Oxford Biobank - fasting insulin and / or glucose and / or insulin resistance as measured by Homeostatic model assessment (HOMA) - insulin resistance in the 40th-60th percentile
• BP<160/100 mmHg with stable antihypertensive therapy for >3 months
• Stable lipid lowering therapy for >3 months
• No contraindications to AZD4017 or prednisolone treatment Study participants who are sexually active with a female partner of childbearing potential must be surgically sterilized, practicing true abstinence (when this is in line with the preferred and usual lifestyle of the subject. Periodic abstinence, e.g. calendar, ovulation, symptothermal, post-ovulation methods, declaration of abstinence for the duration of a trial, and withdrawal are not acceptable methods of contraception) or agree, along with their partners, to use two forms of highly effective methods of birth control (i.e. condom plus another highly effective method defined below), and not rely on barrier methods and spermicide alone, from the time of screening and for the duration of the study. For the proposed clinical study, all study subjects will be male.

For male study subjects whose partner is pregnant, or whose partner is a woman of child-bearing potential (WOCBP) who is established on and continuing to use a highly effective method of contraception, in addition to the stipulations above, males should continue to use a condom (in addition to the highly effective method) for 1 week following the last dose of study drug (5 drug elimination half-lives rounded up to 1 week).

For male study subjects whose partner is not pregnant but is a WOCBP who is not established on and continuing to use a highly effective method of contraception, males should continue to use a condom (in addition to the highly effective method) for 3 weeks following the last dose of study drug (5 drug elimination half-lives plus 2 weeks).

Male study participants must also not donate sperm from the time of screening until 3 weeks after final dose of study drug (5 drug elimination half-lives plus 2 weeks).

Highly effective methods of contraception are defined as combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation (either oral, intravaginal or transdermal), progestogen-only hormonal contraception associated with inhibition of ovulation (either oral [specifically Cerazette™], injectable or implantable), intrauterine device (IUD), intrauterine hormone-releasing system (IUS), bilateral tubal occlusion, vasectomized partner or sexual abstinence.

We would advise that competitive elite athletes do not take part in the study as there is the possibility that the prednisolone could impact upon their athletic performance

Exclusion Criteria:

The participant may not enter the study if any of the following apply:

• Age <18 or >60years
• Body mass index <20 or >30kg/m2
• A diagnosis of diabetes (type 1 or type 2)
• A blood haemoglobin <120mg/dL
• Haemorrhagic disorders
• Anticoagulant treatment
• Renal impairment with estimated Glomerular Filtration Rate <60ml/min
• Abnormal liver chemistry with aspartate aminotransferase, alanine transaminase and/or Gamma-glutamyltransferase and/or bilirubin more than the upper limit of normal
• Glucocorticoid therapy (including inhaled, topical or oral) within the last 6 months
• Concomitant anti-inflammatory medication including NSAIDs, disease modifying anti-rheumatic drugs (DMARDs) / steroid-sparing medications (e.g. methotrexate, sulphasalazine, hydroxychloroquine, azathioprine, leflunomide, biologics [anti-Tumor necrosis factor alpha, interleukin-1ra]).
• Any medical condition in the opinion of the investigator that might impact upon safety or validity of the results - recent (within 2 weeks) or active infection, known liver disease, known thyroid disease, active malignancy, existing inflammatory condition (e.g. inflammatory arthropathy, inflammatory bowel disease, autoimmune disease, connective tissue disease)
• Current evidence of alcohol abuse or a significant history of alcohol abuse, as judged by the investigator.
• Contraindication to any of the study treatments or known or suspected hypersensitivity to the investigational product, compounds of the same class, other study treatments or any excipients.
• Unwilling, or unable, to give informed consent.
• Participation in another investigational medicinal product trial / study within the past 6 months