IN VITRO METABOLISM OF SUBSTITUTED STEROIDS BY RAT LIVER121,2

Abstract

The metabolism of 14 steroids with various structures has been investigated in liver slices. In all cases the rate of destruction was estimated by the Porter-Silber reaction to determine loss of the dihydroxyacetone sidechain; by the BTZ reaction to determine reducing power of sidechain without the 17-hydroxyl; by the absorption at 240 mμ to determine reduction in the Ring-A; and, by the Gornall reaction to determine alteration in reactivity to 2,4 initrophenylhydrozine. Substitution in Ring-A (1:2 ethylenic linkage, 2 methyl) did not change sidechain reaction, but depressed saturation of the Ring-A. Substituents in the 9 position had a similar effect on rate of metabolism. Natural steroids other than cortisone and hydrocortisone appeared to be inactivated much more readily than the substituted steroids. The activity of the substituted steroids cannot be explained solely on the basis of rate of metabolism.