1-Hydrocortisone and Hydrocortisone: Plasma 17-Hydroxycorticosteroid Concentrations in the Dog Following Oral and Intravenous Administration.

The effects of orally and intravenously administered Δ1-hydrocortisone and hydrocortisone on plasma 17-OHCS concentrations in the dog have been studied. Δ1-Hydrocortisone produced higher and more prolonged plasma 17-OHCS elevations than did equivalent doses of hydrocortisone administered orally. The half-life of Δ1-hydrocortisone was found to be 1.37 times that of hydrocortisone. Intravenous administration of these steroids as the hemisuccinates gave lower but somewhat more prolonged elevations in plasma 17-OHCS concentrations than the corresponding free alcohols. It was concluded that Δ1-hydrocortisone was metabolized more slowly than hydrocortisone and suggested that this may explain, at least in part, the enhanced potency of the Δ1-steroid.