AJP - Endocrinology and Metabolism, Vol 246, Issue 4 344-E349, Copyright © 1984 by American Physiological Society
Effect of sucrose feeding on alpha 1-adrenergic responses in rat liver
C. J. Lynch, J. J. Guarino, R. C. Deth and M. L. Steer
A sustained increase in sympathetic nervous system (SNS) activity was
induced by substituting a 10% sucrose solution for the drinking water of
rats fed laboratory chow ad libitum. The effects of increased SNS activity
on alpha 1-adrenergic processes in liver were examined by evaluating three
alpha 1-responses, namely, phenylephrine-stimulated ouabain-sensitive 86Rb+
uptake, 45Ca2+ efflux, and glucose release. Sucrose feeding abolished
phenylephrine stimulation of ouabain-sensitive 86Rb+ uptake and 45Ca2+
efflux and induced a three- to fourfold reduction in the ability of
phenylephrine to stimulate glucose release from liver slices. Pretreatment
with 6-hydroxydopamine markedly reduced liver norepinephrine content. When
6-hydroxydopamine was used to prevent the sucrose-induced increase in SNS
activity, the changes in 86Rb+ uptake, 45Ca2+ efflux, and glucose release
that otherwise followed sucrose feeding were not observed. Sucrose feeding
did not alter binding of the alpha 1-antagonist [3H]prazosin to liver cell
membrane alpha 1-receptors or displacement of [3H]prazosin by the
alpha-agonist epinephrine. These observations suggest that sustained
increases in SNS activity may have profound effects on liver alpha
1-adrenergic events that occur subsequent to hormone-receptor interaction.
