Vitamin D Metabolism in Patients With Endocrine Disorders
Vitamin D Metabolism in Patients With Endocrine Disorders
This prospective controlled interventional study aims to reveal the diversity of vitamin D
 metabolism in patients with certain endocrine disorders (Cushing's disease, acromegaly,
 primary hyperparathyroidism, diabetes mellitus type 1) compared to healthy adults. All
 patients will receive a single dose (150,000 IU) of cholecalciferol aqueous solution orally.
 Laboratory assessments including serum vitamin D metabolites (25(OH)D3, 25(OH)D2,
 1,25(OH)2D3, 3-epi-25(OH)D3, 24,25(OH)2D3 and D3), free 25(OH)D, vitamin D-binding protein
 (DBP) and parathyroid hormone (PTH) as well as serum and urine biochemical parameters will be
 performed before the intake and on Days 1, 3 and 7 after the administration.
Inclusion Criteria:

 -  confirmed diagnosis (arms "Cushing's Disease", "Acromegaly", "Diabetes Mellitus Type
 1", "Primary Hyperparathyroidism")

 -  active phase of the disease (arms "Cushing's Disease", "Acromegaly")

 -  no history of surgical and specific pharmacological treatment (arm "Primary
 Hyperparathyroidism")

 -  HbA1c <8.0% (arm "Diabetes Mellitus Type 1")

 -  absence of the specified endocrine disorders (arm "Control group")

 Exclusion Criteria:

 -  factors associated with vitamin D level

 -  intake of the following drugs during the 3 months preceding the study: vitamin D
 medications; glucocorticosteroids; antiretroviral drugs; antifungal drugs;
 cholestyramine, orlistat; antiepileptic drugs; antidepressants (fluoxetine);
 diuretics (spironolactone); antimicrobial agents (macrolides, tetracyclines,
 isoniazid, rifampin, primaquine); chemotherapy (cyclophosphamide, tamoxifen,
 paclitaxel, ifosfamide, irinotecan, etoposide, vinblastine); immunosuppressants
 (cyclosporin A, tacrolimus, sirolimus); H2 receptor antagonists.

 -  BMI >35 kg/m2

 -  pregnancy

 -  granulomatous disease (sarcoidosis, tuberculosis, histoplasmosis, berylliosis,
 coccidiomycosis)

 -  disease with malabsorption syndrome (Crohn's disease, ulcerative colitis, celiac
 disease, post-bariatric surgery condition, decompensation of chronic
 pancreatitis)

 -  reduced renal function (eGFR <60 ml/min/1.73m2)

 -  laboratory signs of liver failure (hypoalbuminemia, hypoprothrombinemia)

 -  hypercalcemia or risk factors for hypercalcemia

 -  serum total calcium >3.0 mmol/L

 -  myeloma

 -  immobilization

 -  thiazide diuretics intake

 -  allergy to vitamin D drugs

 -  total 25(ОН)D >60 ng/ml (determined by chemiluminescent immunoanalysis)