AJP - Endocrinology and Metabolism, Vol 245, Issue 3 230-E238, Copyright © 1983 by American Physiological Society
Further observations of aldosterone response in barnacle muscle fibers
R. B. Tallitsch
Work with single muscle fibers from the barnacle Balanus nubilus has
revealed that these fibers can be rendered sensitive to external
application of aldosterone by preexposing the barnacle in vivo to the
steroid for 16 h. Experiments investigating the dose-response relationship,
glucocorticoid sensitivity of the preparation, and the role of the
mitochondria in the aldosterone response in this preparation are presented.
It is demonstrated that saturation kinetics may be seen in the
dose-response curve if care is taken to isolate only fibers from animals
that are in midmolt cycle. Data is presented that demonstrated a specific
mineralocorticoid response to aldosterone in this preparation rather than a
combined mineralocorticoid-glucocorticoid response, as has been
demonstrated in other preparations. Experiments investigating the role of
the mitochondrial inhibitors and substrates suggest that aldosterone
modulates Na efflux in barnacle muscle fibers by altering mitochondrial
function, presumably at the level of succinic hydrogenase.
