Cytoplasmic and nuclear uptake of aldosterone in toad bladder: a mathematical modeling approach
Autor: | M. Claire, H. P. Gaeggeler, Bernard C. Rossier, Pierre Corvol, M. E. Oblin, J. L. Steimer, A. Venot |
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Rok vydání: | 1985 |
Předmět: |
Male
Receptors Steroid medicine.medical_specialty Physiology medicine.drug_class Urinary Bladder Toad In Vitro Techniques Biology Models Biological chemistry.chemical_compound Cytosol Receptors Glucocorticoid Internal medicine biology.animal medicine Animals Binding site Aldosterone Cell Nucleus Cell Biology Chromatin Dissociation constant Kinetics Receptors Mineralocorticoid Endocrinology chemistry Mineralocorticoid Biophysics Bufo marinus Female Steady state (chemistry) Mathematics |
Zdroj: | American Journal of Physiology-Cell Physiology. 248:C88-C101 |
ISSN: | 1522-1563 0363-6143 |
Popis: | The mechanism of aldosterone uptake in the epithelial cells of toad bladder was studied using mathematical modeling. Two complementary approaches were used. The first involved analysis of cytosolic aldosterone binding at steady state according to models defined by the sum of independent noninteractive binding sites. The best model describing the experimental data corresponded to two specific binding sites with mean dissociation constant values of 0.20 and 60 nM for types 1 and 2, respectively. The second approach was based on the analysis of cytoplasmic and nuclear aldosterone uptake kinetics at 25 and 0 degrees C in intact bladder. Two models (A and B) were studied. They both implied the existence of two types of aldosterone binding sites as precursors of the corresponding chromatin bound complexes. In model A, nuclear translocation of the two types of receptors was assumed to obey first-order kinetics. In model B, the translocation process for type 1 sites involved a time lag leading to delayed binding to chromatin. Both models were found to fit the experimental data satisfactorily. The fit obtained for model B appeared to be better at low aldosterone concentrations. |
Databáze: | OpenAIRE |
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