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Effect of femtomolar concentrations of hormones on insulin binding by Tetrahymena, as a function of time
Author(s) -
Csaba G.,
Kovács P.,
Pállinger Éva
Publication year - 2008
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.1433
Subject(s) - tetrahymena , hormone , oxytocin , medicine , endocrinology , serotonin , histamine , insulin , peptide hormone , prolactin , motilin , biology , chemistry , receptor , biochemistry
The unicellular ciliate Tetrahymena , contains and binds hormones, characteristic of vertebrates. Earlier experiments demonstrated the effect of extremely low concentrations of hormones. In the present experiments, the effect of various hormones (endorphin, serotonin, histamine, insulin and epidermal growth factor [EGF]) in 10 −15 M, or oxytocin, gonadotropin at 0.001 IU concentrations) on the binding of FITC‐insulin was studied by using flow cytometry and confocal microscopy, after 1, 5, 15, 30 and 60 min. Six of the seven hormones promptly decreased the cells' hormone binding capacity, the exception being EGF, and in four cases (endorphin, serotonin, insulin and oxytocin) the reduction was enormous. The decreased binding was durable. However, in the case of endorphin and oxytocin after 30 min, and in the case of serotonin after 60 min the binding returned to the control level. In the case of oxytocin after 60 min, binding significantly surpassed the control level. Histamine returned to the control level after 15 min, but after that the binding became even lower. EGF provoked special behaviour: it increased hormone binding after 30 and 60 min. The results call attention to the extreme sensitivity of Tetrahymena receptors to hormonal inductions and to its quick response ability. Copyright © 2007 John Wiley & Sons, Ltd.