Reversal of Desoxycorticosterone Inhibition of Heart Beat by Serum Fractions

Abstract

The factor in serum that modifies the cardiac-inhibitory effects of DOC appears to be associated with a protein molecule having a molecular weight of 60,000–70,000. Heating the albumin fraction destroys its activity. Dialysis of serum indicates that one or more dialyzable cofactors are required for full activity of the serum. Of a number of compounds tested for their ability to antagonize DOC, l-cysteine is the most effective while glutathione and dl-homocysteine show slight activity. A study of a number of steroids related to DOC and progesterone revealed that the 21-hydroxy configuration is necessary for cardiac stimulation while progressive reduction at C-11 increases the cardiac inhibiting property of the steroid.