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CGRP Radioreceptor assay: A new diagnostic tool for medullary thyroid carcinoma
Author(s) -
Wimalawansa Sunil J.
Publication year - 1993
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1002/jbmr.5650080411
Subject(s) - pentagastrin , calcitonin , medicine , endocrinology , calcitonin gene related peptide , medullary carcinoma , thyroid , basal (medicine) , thyroid carcinoma , receptor , neuropeptide , secretion , gastric acid , insulin
The Quantitative Analysis Of Immunoreactive Calcitonin (Ict) Is The Assay Of Choice For Diagnosis And Follow‐Up Of Patients With Medullary Thryoid Carcinoma (Mtc). However, In A Small Percentage Of Patients With Mtc Or C Cell Hyperplasia (Cch), Basal And Stimulated Ict Levels May Not Be Significantly Elevated. In These Patients, Calcitonin Gene‐Related Peptide (Cgrp) Radioreceptor Assay (Rra) Can Be Used Complementary To Immunoassay For Ct (Or Katacalcin) For Prompt Diagnosis Of Mtc And Cch. Cgrp Rra Is A Robust, Rapid, Sensitive, And Specific Determinant Of “Receptor‐Recognized” Cgrp (Rr‐Cgrp; Intact Molecule Of Cgrp) Either In Plasma Or In Tissue Extracts. Plasma Rr‐Cgrp Levels Rose > 100% 2–5 Minutes After Stimulation With Intravenous Pentagastrin (Calcium Or Oral Alcohol) ( P < 0.001), Whereas Icgrp Levels Were Raised To A Lesser Degree ( P < 0.01). In Six Patients Who Had A False Positive Ict Response After Pentagastrin Or Had Raised Basal Ict Levels Measured With A Two‐Site Immunoradiometric Assay, Rr‐Cgrp Showed Only A Minimal Change. On The Other Hand, In Patients With Cch (True Positive, N = 8), Ict Was Increased By Only 40% After Pentagastrin But Rr‐Cgrp Levels Rose By 140% ( P < 0.001). No Change In Ict Or Rr‐Cgrp Levels In Plasma Were Detected In Healthy Normal Volunteers After Administration Of Pentagastrin. Therefore, In Addition To The Plasma Ict Levels, Rr‐Cgrp Would Resolve Some Of The Difficult Diagnostic Problems Associated With Mtc And Likely Improve The Specificity And Sensitivity Of Identifying Cch.