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Parathyroid HormoneAka: C-Terminal PTH, N-Terminal PTH, Whole Molecule PTH, Intact PTH, Mid-Region PTH, PTH

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  1. Physiology: Parathyroid Hormone (PTH)
    1. PTH is released by Parathyroid Glands in neck
      1. Parathyroids increase PTH when calcium is low
      2. Parathyroids decrease PTH when calcium is high
    2. Pharmacokinetics
      1. PTH is 84 amino-acid peptide
      2. Circulating half-life: 2-5 minutes
      3. Metabolized by liver and kidney
    3. Mechanism
      1. PTH stimulates Osteoclasts in bone
        1. Osteoclasts mobilize bone calcium
      2. PTH acts at kidneys to increase Serum Calcium
        1. Increases calcium reabsorption
        2. Kidney activates 25-hydroxyVitamin D
          1. Converts it to 1,25-dihydroxyVitamin D3
          2. Increases intestinal calcium absorption
  2. Testing
    1. Tests to avoid
      1. C-Terminal PTH
      2. N-Terminal PTH
    2. Recommended Test
      1. Whole Molecule PTH by IRMA (Mid-region or intact PTH)
        1. Measures C-Terminal and N-Terminal PTH
  3. Interpretation: Normal Serum Calcium
    1. Parathyroid Hormone: 10 to 66 pg/ml
      1. Normal Parathyroid Function
  4. Interpretation: High Serum Calcium
    1. Parathyroid Hormone >66 pg/ml
      1. Primary Hyperparathyroidism
      2. Consider MEN I or MEN II
    2. Parathyroid Hormone 10-66 pg/ml
      1. Familial Hypocalciuric Hypercalcemia
        1. 24 hour Urine Calcium to Creatine clearance <0.01
    3. Parathyroid Hormone <10 pg/ml
      1. Parathyroid Cancer
      2. Granulomatous Disease
      3. Milk-Alkali Syndrome
      4. Adrenal Insufficiency
      5. Hyperthyroidism
      6. Prolonged immobilization
      7. Medication related
        1. Lithium
        2. Theophylline
        3. Tamoxifen
  5. Interpretation: Low Serum Calcium
    1. Parathyroid Hormone >66 pg/ml
      1. Secondary Hyperparathyroidism
        1. Renal Failure
        2. Gastrointestinal malabsorption
        3. Hypomagnesemia
    2. Parathyroid Hormone 10 to 66 pg/ml
      1. Pseudohypoparathyroidism
    3. Parathyroid Hormone <10 pg/ml
      1. Hypoparathyroidism
  6. References
    1. Bakerman (1984) ABCs of Lab Data, ILD, Greenville, NC
    2. Einhorn (2001) CMEA Medicine Lecture, San Diego
    3. Taniegra (2004) Am Fam Physician 69(2):333

Parathyroid Hormones (C0030520)

Definition (CSP)polypeptide hormone secreted by the parathyroid glands which maintains intracellular calcium levels in the body; parathyroid hormone increases intracellular calcium by promoting the release of calcium from bone, increases the intestinal absorption of calcium, increases the renal tubular reabsorption of calcium, and increases the renal excretion of phosphates.
Definition (PDQ)Encoded by human PTH Gene (Parathyroid Hormone Family), secreted (parathyroid cells) 115-aa 13-kDa (precursor) Parathyroid Hormone elevates blood Ca2+ levels by dissolving the salts in bone and preventing renal excretion. PTH defects cause familial isolated hypoparathyroidism. (NCI) Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=489119&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=489119&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C41027" NCI Thesaurus)
Definition (MSH)A polypeptide hormone (84 amino acid residues) secreted by the PARATHYROID GLANDS which performs the essential role of maintaining intracellular CALCIUM levels in the body. Parathyroid hormone increases intracellular calcium by promoting the release of CALCIUM from BONE, increases the intestinal absorption of calcium, increases the renal tubular reabsorption of calcium, and increases the renal excretion of phosphates.
ConceptsAmino Acid, Peptide, or Protein (T116) , Pharmacologic Substance (T121) , Hormone (T125)
EnglishParathormone, Parathormone preparation, Parathyrin, PARATHYROID, Parathyroid extract, Parathyroid Hormone, Parathyroid hormone agent, Parathyroid hormone preparation, Parathyroid Hormones, PTH, PTH - Parathyroid hormone
Spanishagente con hormona paratiroidea, extracto paratiroideo, hormona paratiroidea, hormona paratiroidea intacta, parathormona, preparado con hormona paratiroidea, preparado con paratohormona, preparado con PTH, preparado de hormona paratiroidea, preparado de paratohormona, preparado de PTH
Parent Conceptshormones by function (C0682760), peptide hormone (C0597192), Parathyroid Hormones (C0030520), Tumor Markers, Biological (C0041366), Natural hormone preparation (C0304716), Calcium regulating hormone (C0360589), Bone resorption inhibitor (C0521941), Peptide hormones and their metabolites and precursors (C0582246), Reason not stated concept (C1276325), Thyroid preparation (C0279175)
SourcesAOD, CSP, LCH, LNC, MSH, MTH, PDQ, SCTSPA, SNOMEDCT, USPMG, VANDF
Derived from the NIH UMLS (Unified Medical Language System)



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