Factors influencing the biological activity of orally administered steroid compounds: effect of the medium and of esterification.

Abstract

The influence of the medium (aqueous or oily) and of esterification on the biological activity of some steroid hormones given orally to the rat has been studied. Androgenic compounds were assayed by their effects on seminal vesicle, ventral prostate and levator ani weights in castrated male rats and cortisonelike substances by their effect on thymus, spleen, adrenal and granuloma weights in intact female rats. All tested compounds exhibited an increase in specific activity when administered orally in oily solution instead of aqueous suspension. The steroid compounds (i.e. androstanolone and in some instances prcolnisone) esterified with short chain fatty acids also exhibited a greater specific activity than the free steroid compounds. Some hypotheses have been advanced to elucidate possible mechanisms by which lipidic solvent or esterification may potentiate the specific activity oforally administered steroid compounds.