Comparison of the amount and demonstrability of endogeneous hormones and bound insulin after paraformaldehyde and Edac fixation in Tetrahymena

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The amount of three endogeneous hormones (insulin, β-endorphin, and triiodothyronine) and FITC-insulin binding were studied in Tetrahymena using confocal microscopy and flow cytometry after paraformaldehyde (Pf) or carbodiimide (EDAC) fixation. After EDAC fixation the measurable hormone content was 2.5x, 4x, 6x more, respectively, related to Pf fixation (significance: p<0.001). This means that EDAC, which causes crosslinking between COOH and amino groups inside a molecule and between molecules could inhibit the escape of hormones during the procedure. However, FITC-insulin binding was also threefold after EDAC fixation which means that some other effects must be considered. The results show that 1) EDAC fixation is more suitable to watch the whole hormone content in a cell (in Tetrahymena, at present); 2) more vertebrate-like hormone is present in Tetrahymena, than it was believed before and 3) triiodothyronine is also present in Tetrahymena (first observation).

Original languageEnglish
Pages (from-to)455-459
Number of pages5
JournalActa Protozoologica
Issue number4
Publication statusPublished - Nov 1 2006


ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)

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