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Binding of cortisol and its degradation products by human serum albumin

1967; Elsevier BV; Volume: 56; Issue: 6 Linguagem: Inglês

10.1002/jps.2600560605

1520-6017

K. J. Kripalani, Donald L. Sorby,

Stress Responses and Cortisol

The rate of degradation of the 17-dihydroxyacetone function of cortisol has been measured in a phosphate buffer system, pH 7.4 and ionic strength 0.16, at 15.0°, 25.0°, and 35.0°. The results correspond favorably with data in the literature for degradation of prednisolone under similar conditions. The binding of cortisol and its degradation products to human serum albumin was measured at 25.0° by an equilibrium dialysis procedure. The degradation products were found to be bound more strongly than was cortisol, but did not appear to compete with cortisol for binding sites on the protein molecule. In systems having a constant concentration of total corticosteroid, the apparent binding constant of total steroid increases as the fraction of the material present as degradation products increases. The results of this research are important to the design of experiments which attempt to study the binding of steroids containing the 17-dihydroxyacetone function to serum proteins. The rate of degradation of the 17-dihydroxyacetone function of cortisol has been measured in a phosphate buffer system, pH 7.4 and ionic strength 0.16, at 15.0°, 25.0°, and 35.0°. The results correspond favorably with data in the literature for degradation of prednisolone under similar conditions. The binding of cortisol and its degradation products to human serum albumin was measured at 25.0° by an equilibrium dialysis procedure. The degradation products were found to be bound more strongly than was cortisol, but did not appear to compete with cortisol for binding sites on the protein molecule. In systems having a constant concentration of total corticosteroid, the apparent binding constant of total steroid increases as the fraction of the material present as degradation products increases. The results of this research are important to the design of experiments which attempt to study the binding of steroids containing the 17-dihydroxyacetone function to serum proteins.