Acrihellin, a cardioactive steroid escaping from the organ-bath.

The concentration of acrihellin rapidly declines in oxygenated Tyrode-solution, because the compound escapes from the organ-bath being enriched in droplets sprayed from the surface of the bubbled solution. As checked by radiochromatography, acrihellin remains chemically unaltered during this process. Hellebrin and hellebrigenin persist in gassed Tyrode-solution, suggesting that the 3 beta-substituent dimethylacrylic acid endows acrihellin with amphiphilic properties, thus promoting its enrichment at gas-water interphases. Measurements of the inotropic effects in guinea pig left atria performed at concentrations of acrihellin kept constant yielded a dose-response curve, which closely resembles that of the conventional cardioactive steroid ouabain.