21-HYDROXY-6,19-OXIDOPROGESTERONE - A NOVEL SYNTHETIC STEROID WITH SPECIFIC ANTIGLUCOCORTICOID PROPERTIES IN THE RAT

In the rat, the conformationally highly bent steroid 21-hydroxy-6,19-o xidoprogesterone efficiently displaces [H-3]corticosterone from thymus -glucocorticoid receptors and blocks type II receptors in kidney cytos ols but competes with neither [H-3]aldosterone for kidney-mineralocort icoid receptors nor [H-3]progesterone for uterus-progesterone receptor s. It evokes Na+ retention only at very high doses (similar to 100 mu g/100 g of rat weight) and is unable to induce tyrosine aminotransfera se or to increase glycogen deposits in rat liver. When coincubated wit h corticosterone or dexamethasone, 2.5 mu M 21OH-6OP inhibits 80% of t yrosine aminotransferase induction. It may therefore be used experimen tally as an antiglucocorticoid virtually lacking mineralocorticoid or glucocorticoid properties as well as affinity for mineralocorticoid or progesterone receptors.