PROTECTIVE ACTION OF CARDIAC GLYCOSIDES AND ADRENAL CORTICAL HORMONE AGAINST THYROXIN1

Abstract

Thyroxin was administered to mice (10, 25, 50 [gamma]/g. body wt.) and guinea pigs (0.25 and 1.0 [gamma]/g. body wt.) over 2-wk. periods. Consistent wt. loss occurred in guinea pigs but not in mice. Adm. of natural adrenal cortical hormone, and of desoxycorticosterone acetate (4 [gamma]/g. daily) partially prevented this wt. loss. Small dosage of cardiac steroid glycosides (0.2 [gamma]/g. body wt. of mixture of lanatosides A B and C for 2-6 days prior to and during thyroxin adm.) produced an effect similar to that obtained with adrenal cortical hormone. The histologic changes in the adrenal cortex were similar in those animals receiving adrenal cortical hormone-thyroxin and cardiac glycosides-thyroxin, respectively. Larger dosage or prolonged adm. of cardiac glycosides to guinea pigs receiving thyroxin fails to prevent or actually increases wt. loss, although all dosages of cardiac glycosides used were non-toxic to normal animals.