Signal Transduction and Ion Permeability in Adrenal Glomerulosa Cells
In recent years it has become apparent that many types of endocrine cells exhibit electrical activity, an important property with regard to stimulus-secretion coupling. This is also true for adrenal glomerulosa cells; from the early work of Matthews and Saffran,1) it has been known that adrenal cells have a negative resting potential that is influenced by the binding of ACTH to specific receptors. Adrenacorticotropin (ACTH) stimulates aldosterone secretion from adrenal glomerulosa cells. The secretion of this hormone is under the control of at least three stimuli: angiotensin II, external potassium ions, and ACTH. Different transduction mechanisms have been proposed in relation to the effects of these factors and include cAMP formation, regulation of cytosolic free calcium through the phosphatidylinositol system, and ion channel modification, protein kinase C activation, and modification of the membrane potential. This situation is summarized in Fig. 1.
KeywordsAtrial Natriuretic Peptide Aldosterone Secretion Aldosterone Production Inhibitory Phase Potassium Permeability
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- 1.Mathews, E. K., and Saffran, M., 1973, Ionic dependence of adrenal steroidogenesis and ACTH-induced changes in the membrane potential of adrenocortical cells, J. Physiol. 234: 43–64.Google Scholar
- 14.Mattews, E. K., 1986, Calcium and membrane permeability, Br. Med. Bull. 42: 391–398.Google Scholar
- 18.Higashida, H., and Brown, J. A., 1986, Two polyphosphatidylinositide metabolites control two K+ currents in neural cells, Nature 225: 323–333.Google Scholar