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Ouabain as a mammalian hormone.
Wilhelm Schoner1, Natali Bauer, Jochen Müller-Ehmsen
1Institute of Biochemistry and Endocrinology, Justus-Liebig-University Giessen, Germany. wilhelm.schoner@vetmed.uni-giessen.de
Annals of the New York Academy of Sciences
|May 24, 2003
Summary
Endogenous ouabain, a steroid hormone, rapidly changes with exercise and is regulated by epinephrine and angiotensin II. Its elimination may involve IgM complexes, explaining differences in ouabain and digoxin effects on hypertension.
Area of Science:
- Biochemistry
- Endocrinology
- Immunology
Background:
- Endogenous ouabain is a rapidly acting hormone influenced by physical exercise, epinephrine, and angiotensin II.
- Cardiac glycosides, like ouabain and digoxin, play roles in arterial hypertension.
- The liver is a key organ for steroid metabolism and elimination.
Purpose of the Study:
- To investigate the binding globulins for cardiac glycosides in bovine plasma.
- To understand the role of identified complexes in the hepatic elimination of cardiotonic steroids.
- To elucidate the basis for differential actions of ouabain and digoxin in arterial hypertension.
Main Methods:
- Searched for specific binding globulins for cardiac glycosides in bovine plasma.
- Identified the d allotype of the micro chain of IgM.
- Investigated interactions between IgM, cardiotonic steroids, and cholesterol.
Main Results:
- Identified the d allotype of the micro chain of IgM as a binding globulin for cardiotonic steroids and cholesterol.
- Hypothesized that these IgM complexes are involved in the hepatic elimination of cardiotonic steroids.
- Suggested that differences in Na(+),K(+)-ATPase signaling explain ouabain and digoxin's distinct roles in hypertension.
Conclusions:
- The d allotype of IgM is a potential binding globulin for cardiotonic steroids.
- IgM complexes may facilitate hepatic elimination of endogenous ouabain.
- Disparities in Na(+),K(+)-ATPase signaling pathways underlie differential effects of ouabain and digoxin on arterial hypertension.