AJP - Endocrinology and Metabolism, Vol 241, Issue 5 406-E409, Copyright © 1981 by American Physiological Society
Mineralocorticoid activity of 19-nor-DOC and 19-OH-DOC in toad bladder
R. D. Perrone, J. H. Schwartz, H. H. Bengele, S. L. Dale, J. C. Melby and E. A. Alexander
Adrenal enucleation is followed by a period of increased sodium
reabsorption thought to be due to excess mineralocorticoid activity.
However, it has not been demonstrated that increased production of any
known mineralocorticoid accounts for this antinatriuresis. Recently,
19-hydroxydeoxycorticosterone (19-OH-DOC) was found in incubates of
regenerating adrenal capsules 3-4 days postenucleation and
19-nordeoxycorticosterone (19-nor-DOC) was identified in the urine of rats
with regenerating adrenals. Because it was possible that these hormones
might play a role in the sodium retention after adrenal enucleation, we
compared the mineralocorticoid activity of these steroids to aldosterone
using the toad bladder. Using short-circuit current as a measure of sodium
transport, we found that 19-OH-DOC (10(-8) M) had no significant effect on
sodium transport. However, 19-nor-DOC (10(-8) M) increased sodium transport
to a degree not different from aldosterone (10(-8) M). Furthermore, the
onset of action, duration of activity, and inhibition of effect of
19-nor-DOC by spironolactone were not different from that of aldosterone.
We conclude that 19-nor-DOC exhibits a significant effect on sodium
transport and thus has the potential to play a role in the sodium retention
following adrenal enucleation. Under the conditions of these studies,
19-OH-DOC exhibited no effect on sodium transport.
