Effect of ketone bodies on measurements of plasma 17-hydroxycorticosteroids as Porter-Silber chromogens

Porter-Silber chromogens were measured in pooled human plasma before and after the in vitro addition of acetone or beta hydroxybutyric acid in concentrations as high as 100 mg. per 100 ml. plasma. Measurements of Porter-Silber chromogens and ketone bodies were also made on plasma from 2 starving obese female patients and 3 starving dogs. No elevation of the Porter-Silber chromogens was observed in the in vitro studies. Plasma Porter-Silber chromogens, as well as ketone bodies, were elevated in the plasma of the starving women, but the elevation of the plasma ketone bodies was over 400 times greater than the Porter-Silber chromogen levels. The relationship between ketone body and Porter-Silber chromogen levels was variable. In the dogs, mean plasma Porter-Silber chromogens rose from a prestarvation level of 4.4 μg per cent to 7.2 μg per cent at the end of 10 days' starvation, whereas, plasma ketones rose from 177 μg per cent to 3,377 μg per cent during the same period. From these observations it is concluded that acetone and beta hydroxybutyric acid added to plasma in vitro do not produce an elevation of Porter-Silber chromogen values, and that elevated plasma levels of these ketones are not responsible for the marked increase of plasma Porter-Silber chromogens observed in humans during starvation. Unlike the human, the dog shows only a slight increase in plasma Porter-Silber chromogen levels during starvation.