Blood Pressure and Metabolic Effects of 9-Alpha-Fluoro-Hydrocortisone in Sheep

Abstract

9αfluorohydrocortisone (9αFF) is an analogue of hydrocortisone with both ‘mineralocorticoid’ and ‘glucocorticoid’ activity. 9αFF was infused at 0.2, 0.63 and 2.0 mg/day for 5 days to intact conscious trained sheep. At high dose (0.63 and 2 mg/day) 9αFF raises blood pressure in sheep, (mean arterial pressure rise 32 and 29 mm Hg respectively on the fifth day), lowers plasma [K], raises plasma [Na] and produces initial urinary sodium retention. At low dose (0.2 mg/day) blood pressure is raised (+ 16 mm Hg on day 5) but plasma and urinary electrolytes are unaltered. 9αFF had no effect on water intake or urine output at any dose. In all animals withdrawal of 9αFF was associated with a natriuresis. On the basis of its affinity for ‘mineralocorticoid’ and ‘glucocorticoid’ ovine renal receptors, 9αFF at low dose may raise blood pressure by mechanisms not simply related to its ‘glucocorticoid’ and/or ‘mineralocorticoid’ action.