The existence of two interconvertible forms of 18-hydroxycorticosterone: Is one of them an active pŕecursor of aldosterone?

18-Hydroxycorticosterone exhibits a spontaneous interconversion between two forms separable by paper chromatography, a and b. Upon acetylation, both give rise to at least one compound having identical chromatographic properties irrespective of the basic form utilized. Both forms present different chromatographic patterns upon elution from Sephadex LH 20. The less polar on paper strips ( a) also migrated closer to the solvent front after gel filtration. In repeated experiments, a proved to be a better precursor for aldosterone-like material than b. In at least one case, these results could be confirmed for purified aldosterone. Also, the uptake of a by adrenal tissue is higher than that of b.