Aldosterone plasma radioimmunoassay interference by a spirolactone metabolite.
The plasma aldosterone radioimmunoassay developed by Ito et al. was found to be non-specific for aldosterone following administration of the spirolactones, spironolactone and canrenoate-K, in rabbits, dogs and humans. The assay interfering principle was identified as a hydroxylated derivative (M-B) of canrenone, which itself is a metabolite common to both spironolactone and canrenoate-K. The metabolite M-B possessed a high cross-reactivity to the 21-hemisuccinate aldosterone antibody relative to other spirolactones. A modified procedure was developed specific for plasma aldosterone in the presence of M-B. Following single doses of spironolactone and canrenoate-K, aldosterone plasma levels were unchanged in humans and in dogs and decreased in rabbits.
D000450:Aldosterone / Q000097:blood*; D000818:Animals; D002191:Canrenoic Acid / Q000097:blood*; D003429:Cross Reactions; D004285:Dogs; D006801:Humans; D013058:Mass Spectrometry; D011245:Pregnadienes / Q000097:blood*; D011817:Rabbits / Q000276:immunology; D011863:Radioimmunoassay; D013045:Species Specificity; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013148:Spironolactone / Q000097:blood*; D013997:Time Factors
D011245:Pregnadienes; D013148:Spironolactone; D000450:Aldosterone; D002191:Canrenoic Acid