The effect of norepinephrine and dibutyryl cyclic adenosine monophosphate on cation transport in duck erythrocytes |
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Authors: | D H Riddick F M Kregenow J Orloff |
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Affiliation: | From the Laboratory of Kidney and Electrolyte Metabolism, National Heart and Lung Institute, National Institutes of Health, Bethesda, Maryland 20014. |
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Abstract: | Freshly prepared duck erythrocytes, incubated either in plasma or an isotonic synthetic medium containing norepinephrine ([K] of both media ∼ 2.5 mM), maintain water and electrolyte composition in the steady state (upper steady state) for at least 90 min. If incubated in the synthetic medium without norepinephrine or in plasma to which a β-adrenergic blocking agent (propranolol) is added, the cells lose both water and electrolyte (predominantly KCl) until a new steady state is reached (lower steady state). Reaccumulation of water and electrolyte from isotonic solutions toward the upper steady-state levels requires the addition of norepinephrine and KCl. Reaccumulation is maximal when the concentration of K and norepinephrine in the medium is 15 mM and 10-7M, respectively. Dibutyryl cyclic-AMP (10-2M) mimics norepinephrine in lower steady-state cells. Although an analogous effect in upper steady-state cells was not established with certainty, it is proposed that the catecholamine-induced net changes in water and electrolyte movement in duck erythrocytes are a consequence of stimulation of the activity of a membrane-bound adenyl cyclase system. |
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